Mac OS tip for Error Code -36

By Phil Plait | March 30, 2008 2:34 pm

I just had a problem on my Mac that I could not solve anywhere on the web, but wound up solving on my own. If you don’t own a Mac, then move along, but if you do, this may save you hours of frustration.

I have a Western Digital 500 Gb external hard drive (which I named Colossus for those who get it). It’s formatted as Mac OS Extended (journaled). It came FAT32 of course, but that has issues — like it won’t allow files bigger than 4Gb which is simply stupid. So I reformatted it, and everything has been cool… until last week.

I tried moving a movie file over today by dragging it off the Desktop and onto my external drive, and I got an error message saying Finder couldn’t move it because all or part of the file had a problem. This is the dreaded "Error Code -36" message, which I assume Apple stole from Microsoft because it is a generic message which tells you nothing.

Anyway, I searched high and low on the web for some way to fix this, but nothing helped. I changed permissions, I checked for errors using disk utility, and lots of other things. Nothing worked.

I also noticed that text files moved over just fine. So did an XLS file. Just not AVIs.

I was scratching my head, and then suddenly thought: wait a sec! OSX (I’m still using 10.4 by the way) is based on Unix. I know lots of Unix!

So I opened a terminal and cd’ed to the external drive directory. Everything looked fine. Permissions and everything were set correctly.

What I did next appears to have fixed the problem: instead of using Finder, in the terminal window I used the Unix command mv to move an AVI file from my internal drive to the external. It looked something like this:

prompt%> mv /Users/phil/Desktop/movie.avi .

… which translates to "Move the file from my desktop to the current directory" (remember, I had already cd’ed to my external drive’s movie directory, which looks like /Volumes/Colossus/movies).

That worked. Aha! Maybe the problem was with Finder! So I went back and tried to move another movie file (similar to the first) using drag-and-drop, and this time it worked. W00t!

I’m not sure what was going on; maybe Finder got all bollixed up, and by directly moving the files in Unix Finder was able to find its way back to reality. I don’t know why this worked. But if you ever get the Error Code -36 message, try this. I just made myself very happy after being very sad.


Comments (84)

  1. K. T.

    This may or may not be similar to a problem in Windows. When you click on an .AVI (or other video) in Windows Explorer it displays the length, resolution, etc in the status line. If you click and drag that to a new location (or delete it or something along those lines) before it has time to read that information (which can take a long time if the video is large) it fails to move the file because it is still scanning the video. There is a registry entry to keep Windows from trying to find out information about a video that a Google search should turn up (or one could single click the file, wait a little while until Windows Explorer has finished messing around, then drag it to a new location or delete it.)

    Afraid I don’t know enough about MacOS to know if the problem is similar, but I was reminded of the Windows problem.

  2. And the moral of the story is: UNIX is your friend, boys and girls. Learn how to use it. Besides, any idiot can drag-and-drop, but if you use the command line, you look like a real geek.

  3. The next computer I’m buying to replace the clunker I have now is going to be a Mac. I don’t especially like Macs, I just hate Windows Vista with a vengeance. An error like the one you just highlighted wouldn’t get fixed for a long time and then the solution would come in a clunky service pack that creates more problems than it solves.

  4. marko

    Phil, you’ve just went way up in my “cool” book for having an all-lowercase Unix username! 😀

    Maybe the Spotlight indexing demon tried to search that huge movie file for keywords, keeping the file open while you tried to move it.

    I use to copy CD tracks that the Finder refused to access with the bash, no problem.

    Who’d have thought that Apple still has uncharted spots for error numbers. At least an “unknown error” would have been more appropriate, alas just as “helpful”. :-[

  5. Glenn

    Be careful if you’re using standard Unix commands on Classic files. I bleeped up a “backup” when I was shifting files on a machine that was set up to dual-boot between MacOS 9 and MacOS X when I did an ‘mv’ on a file with a resource fork.

    Copied the (empty) data fork and dropped the resource fork completely.

    I tried googling for “MacOS Classic Error codes” and stumbled on a help page for “MacOS Fork Converter” that lead into the Carbon reference guide, which was a real trip down memory lane. I first got into Mac’s when a buddy and I decided we’d like to write an accounting package.

    Never did get it written.

    Digging into the ‘Carbon’ documentation tells me that ‘-36’ is “ioErr” which is a generic I/O error. Probably a glitch at the electrical level or a very low-level driver error.

    So I’m afraid your ‘fix’ has a pretty good chance of being cargo-cultish.

  6. Glenn

    Oh, yeah, and the other thing I discovered in the aftermath of that bad backup:

    man CpMac

    CPMAC(1) BSD General Commands Manual CPMAC(1)

    /Developer/Tools/CpMac — copy files preserving metadata and forks

    /Developer/Tools/CpMac [-rp] [-mac] source target
    /Developer/Tools/CpMac [-rp] [-mac] source … directory

  7. maybe this finder problem has something to do with a bug in the security updates or something, because i had the same problem recently.
    Couldn’t move a movie file from my optical drive to my hard drive, but it worked from the command line.
    I was glad that i could remember the unix command, > cp /… in this case.

  8. Glenn, I’m not so sure; googling “Mac OSX error code 36” yielded lots of people complaining on fora of this very problem.

    The movie files had been sitting on my hard drive for days, so I don’t think there was any ongoing process poking at them. And if there were, why would bypassing the Finder for a Unix command work and fix the Finder issue?

    It’s weird, but it worked.

  9. I should note that I used “cp” first to make sure I didn’t screw up the file and then not have it still sitting on my internal drive. Once that worked, I used “mv” for a second file. When that worked too I used the Finder; I abbreviated the description of what i did in my post.

  10. Chip

    I’m still discovering new ways to use (and not use) Finder after getting a MacBook Pro OSX with extra memory plus external hard drive, devoted entirely to MOTU Symphonic Instrument, (software tools that sample every instrument and combination in a symphonic orchestra and chorus playing or singing every note in their ranges, with additional tools to create practically every articulation.)

    Sometime seems to take almost as much memory to operate as NASA uses to launch and run the Mars Rovers. 😉

  11. Glenn


    If I’m right and it was a transient error, then doing the ‘mv’ didn’t “fix” anything, it just succeeded because the error didn’t recur.

    It’s excruciatingly common in the tech support field to hear reports that start, “The last time this happened, I did ‘x’ and that fixed it but it didn’t work this time.” And the ‘x’ almost never has anything to do with the typical root cause of the reported problem.

    Or there may be some issue with the Finder caching data it shouldn’t, and the cache got flushed when you did your ‘mv’ command. Computers are so complicated these days it’s hard to tell.

    I had a bug in a release at work a couple of months ago where something using an ancient programming language ‘worked’ for years (literally) until I replaced a ‘shell call’ with a function that used the Windows API to launch the child program, so that we wouldn’t get annoying popup windows. Turns out the ‘built in’ shell-out triggered memory behavior that hid a long-standing design issue in the way we did customer-specific code.

    So despite my instinctive reaction, you might be right; it might have really fixed it. Or, you might be seeing Steve Jobs’ face on your toaster. Just no way to know unless you’re willing to spend a month trying to repeat the experiment.

    Apropos of my comment about wrecking my data by doing “mv” at the command level, I found this at the bottom of the man page I quoted above:

    As of Mac OS X 10.4, the cp command preserves metadata and resource forks of files on Extended HFS volumes, so it can be used in place of CpMac.

  12. Glenn

    Last “PS” I promise. Here’s the link to common “File Manager” error codes when programming using the “Carbon” (aka ‘classic’) API:

  13. pcarini

    Moral of the story: The command line is cool, and *nix wins.

    I miss the days when you could go to a command prompt in Windows and make changes that the OS didn’t want you to do. Windows is still a necessity for me because I play games on my compy, DirectX was the smartest thing Microsoft ever did for themselves imho.

    Anyone who likes the *nix command line _must_ get Cygwin for their Windows machines. I use cygwin almost daily for simple things like find and grep, because the Windows version of those functions are much slower and far less accurate.

  14. Haven’t seen that one since my recent purchase of a Mac laptop, but when you add a “task” to your calendar and your Mail stops working, I can walk you through how to fix that in under thirty seconds. (Thanks to a half hour of searching the web for a solution.)

  15. Mike Torr

    Well, I had already decided to get a Mac in a month or two. Now I’m positive about it. I knew the link with UNIX was there, but this just gave me such a nostalgia rush (I grew up with C under UNIX).

  16. Chris`

    pcarini: you can still do that using an elevated command prompt in windows vista. Just run cmd.exe as an administrator (right click it, run as admin).

  17. Colossus? No, I don’t get the reference Dr. Forbin.


  18. Reminds me of a problem I’ve often had in Windows by which Explorer won’t let me delete movie files. It might be a ‘scanning file’ thing as it won’t, it won’t… it will!

    But I did have one file recently it just wouldn’t let me delete no matter how much time I gave it to think. Fortunately & del did the trick.

    (I think things got partially screwed by due to a program I loaded that preemptively tried to lock any and all avi files and the deleted files wouldn’t disappear from Explorer until I rebooted. That program (something to do with my webcam) has since been killed.)

  19. John

    I believe that part of the problem lies in how the finder copies/moves things versus the ‘cp’ or ‘mv’ commands. Unless you tell them to, cp and mv dont do verification on the file, whereas I believe that the finder does (not sure if it’s md5 hash or something similar).

    If it’s disk sector related (error 36 is an I/O one as mentioned before), then moving other files shouldn’t necessarily reproduce the problem.

    What happens if you attempt to drag and drop the original file *back* to the mac using the finder?

  20. Hank

    Call me crazy but I find myself working way faster in the terminal than in Finder.

  21. Hank, I also think the Finder is a bit crap. I switched from PC to Mac five months ago, and I really miss the possibility to create a file then and there, rename it, and open it with an app I like. Or perhaps I just haven’t found the way to do it yet.

    The other thing is that crashed apps are much easier to remove in the terminal. Remember, “kill -9” and “rm -rf” are your friends… 😉

  22. I work on a Linux command line every day at work and it is most efficient. Love it. And writing ‘for’ loops for tedious repetitive tasks is a snap. Windows ‘for’ loops suck. Running tasks in the background for the *nix OS’s is simple as well. I haven’t used a Mac for a very long time, but I’d certainly consider it since it’s basically Linux under the hood. My next computer will likely not be Windows.

  23. DW

    I must congratulate you on what is a fabulously typical reductionist approach to problem solving! (“If I ignore the function of the failing component of the system, the problem goes away”).

    The assumption that the error code is “copied from Microsoft” is grossly inaccurate; computers are full of all sorts of little numbers, and it should be expected that occasionally they bubble through to the surface regardless of operating system.

    The number in question looks like a UNIX ‘errno’. After consulting /usr/include/sys/errno.h I see that it is ERANGE, which is returned by the operating system kernel when a program requests information about an object that cannot be represented using the types requested. E.g. a 32-bit signed number (range -2147483646..2147483647) is not sufficient for representing file sizes over 2047.99GiB.

    This is probably a bug in Finder or one of the tools it is using underneath the surface, and should probably be reported to Apple. For what it’s worth on Leopard the operation you describe with this type of filesystem does not produce the same error.

    I trust that your religious assumptions aren’t so grossly concocted!

  24. Doug Ellison

    Oh – you’re gonna LOVE the Regents St Apple Store in London on the 17th :)

  25. Glenn


    It looks like a UNIX code, but it isn’t. It *is* an arbitrary integer, but “Classic” MacOS (which the Finder is emulating) used a different range of integers to report errors than Unixes do.

    I don’t know if you checked errno.h on a MacOS box or another Unix box, but you’ll notice that the error is negative, like the MacOS errors were, not positive like the values found in the ‘errno’ variable…

  26. LongTimeListener

    Are you directly connected to the drive or networked to it? Because WD drives had a bit of a hiccup trying to prevent ‘copyright infringement’ :

    In some configurations, you can’t copy avis, mp3s etc.

    Of course it might also be Finder doing more than it needs to to move the file!

    Keep up the good work,

  27. I’ve only been skimming the blog for a few months, and I’m still recuperating from severe brain damage, so I really can’t tell if this thread has some ingeniously calculated parodies, or if some of the authors are just lucky and wrote parodies by accident.

    Maybe I’m just too reductionist, though, but I’m still going to try to submit this comment using the “submit comment” button.

  28. JT

    I suggest the use of copy, rather than move, in case the operation fails in a bad way.

  29. chief

    Had a problem moving a MPG file (3.5 GB) to another drive. solved it by making the partion a network drive (sharing) even though there is no network.

  30. Huh, interesting. I have a MacBook (now) dualbooting between Tiger and Ubuntu Gutsy, and never had any problems transferring files (sometimes large movie files) to my external HD. Now, Gutsy, on the other hand… my external HD will be working perfectly for days, and then all of a sudden will refuse to let me copy a file over from my desktop to a folder some four or five levels down on the external. Says I don’t have permission to do so, and no amount of (un)mounting, logging out/in, rebooting, etc, will fix it. The trick is I have to boot into Tiger and then reboot into Gutsy, and I can copy things over no problem.


  31. Ian


    The assumption that the error code is “copied from Microsoft” is grossly inaccurate; computers are full of all sorts of little numbers, and it should be expected that occasionally they bubble through to the surface regardless of operating system.

    I’m pretty sure that BA’s comment there was intended to be tongue-in-cheek.

  32. Mac OS X’s Unix layer is by far one of the most hidden benefits of being a Mac user. There are lots of things you can do in Unix that you just can’t do as easily in the Finder. (grep, diff, etc…) Beyond that, running things like tomcat or mysql makes it even better. It’s too bad Apple doesn’t advertise this more, though I do see why. The average user doesn’t want/need to use a command line. They just don’t know what they’re missing!

  33. Curious as to what was the actual filename you moved?

    If you copy it back to the desktop, does it start failing again?

    Can I assume that non-avi files dragged from the same folder succeeded? (Or were the other file types in other folders?)

    Also, I’m not sure if you should be praised or condemned for using the technically-correct (I think) “fora”.

    (I haven’t done any serious Mac work since the Mac XL, but I use Unix every day.)

    And yes, a 4GB filesize limit is pretty silly on a 500GB drive, but that’s the limit of FAT32, which is simply an “enhanced” version of FAT from MS-DOS 1.0’s 360K floppy days. They could put NTFS on it, but then Win95/98/Me couldn’t use it. (And yes, I agree that keeping compatibility with such systems is also silly nowadays.) Can Macs use NTFS?

  34. Bruised my head when I fell asleep reading this post.

  35. Ryan

    …the dreaded “Error Code -36” message, which I assume Apple stole from Microsoft because it is a generic message which tells you nothing.

    You forget that Apple *invented* the useless error message:

  36. Raja99

    Pardon me for jumping in. One way to double-check whether the copy worked is to use ‘md5’ at the command line, e.g.,

    md5 monkeysAndMonolith.avi
    md5 ~/monkeysAndMonolith.avi

    If your original file and the new copy yield the same checksum, you can be confident that the file data was copied correctly. (Unless you’re *incredibly* unlucky; the odds of two differing files having the same checksum are something like 1 in 3.40282367 × 10^38.) The md5 command won’t address the issue of whether your file *meta*data was copied correctly, but that’s probably not an issue for an AVI file.

    Hope this helps.

  37. Wayne

    You guys are still using Finder? When I started using OSX for work (at Goddard) back in 2005 I hated it until I discovered Path Finder
    Does everything you wish Finder did (like optionally sorting folders separately from files like Windows) plus lots of stuff you never thought to ask for. I still hate using a Mac that doesn’t have it on there.

    I’m still on 10.4 as well, and my Path Finder is even older, so this may be less relevant than it used to be, but definitely still worth checking out.

  38. Pop

    All this discussion on Unix, Mac, Windows, etc. is just boys showing off to each other who has the biggest pen…, er, ah, biggest… um, hard drive. Yeah, that’s the ticket.

  39. TheBlackCat

    Can Macs use NTFS?

    NTFS-3G, which I use on Linux for accessing NTFS partitions, may also be available for OS X. Mac has native read support but not write support, as does Linux. NTFS-3G provides reliable write support, although it apparently does not support permissions very well. It is often included in Linux distros, but you probably have to download it yourself for Mac. Looks like you can get precompiled binaries for it here:

    You also apparently need the Mac version of FUSE, which NTFS-3G depends on.

  40. Jean-Denis Muys

    Error -36 is not an Errno error number. It’s inherited from the old pre-Mac OS X operating system way back when it was not Unix based.

    It means I/O error, but that *usually* translates to hardware failure, either at Read or Write time.

    In your case, it’s probably at Read time.

    Such an error *might* be transient on hard disks, which would explain while the “cp” command worked. Another reason why it might have worked and not the Finder, is if the Read error was on metadata.

    In any case, I would strongly recommend a low-level check of the Hard disk, using any utility. Alternatively, reformat it using the Erase option: this will trigger the remapping of any bad hard-disk sector.

    And yes, the Mac is a joy to use. Did you try iMovie ’08 for your videos? While lacking some advanced features (especially in the audio department), I think it would be quite nice for the kind of videos you put out.



  41. dziban

    Could have sworn error code -36 meant “data corruption due to cosmic ray strikes”, but maybe thats error -13.

  42. Nonsanity

    When you get errors moving files or opening external drives, you can try to restart Finder first. This can be done by option-right-clicking the Finder’s icon in the dock, or choosing Force Quit… from the Apple menu.

    But a far better solution, one that’s less likely to have bad results, is to just reboot. Some external drives come with drivers that are just out-and-out bad. My latest external drive, a 2TB FW800 job, came with a driver that I stupidly installed. My system became VERY unstable afterwards. It was fine and dandy after digging that driver out by the roots.

    Moral: DON’T install external drive drivers. OS X has all you need to use them already. And if terminal file operations succeed when the Finder spouts errors, its a good time to restart Finder – or the whole computer to be safe.

  43. Sarcastro

    Diskwarrior that puppy!

    Seriously, you may well have a bad sector. At least run Repair Disk from the Disk Utility app on it. And fsck it a few times from the CLI.

  44. marko

    Good idea, Sarcastro. I sporadically do the following:

    # . . . list what’s mounted . . .
    $ mount
    /dev/disk0s2 on / (local, journaled)
    devfs on /dev (local)
    fdesc on /dev (union)
    # . . . flush IO buffers . . .
    $ sync
    # . . . check what’s mounted (requires root to do) . . .
    $ sudo fsck_hfs -nf /dev/disk0s2
    # . . . should finally result in . . .
    ** The volume […] appears to be OK.

    Phew! :-) Rinse, repeat for other mounted volumes.

  45. Clair

    I dig Path Finder, but more times than not, I use the shell for most operations.

    I love the fact OS X is certified UNIX. Having been in a UNIX world for so many years, it was nice to work with it. Of course, now I’m at a job which is 100% the opposite, Windows. And they look at me funny when I mention anything about UNIX. :)

    Anyway, I only found a handful of useful reasons you could’ve gotten the error. I’d check the drives with something like DiskWarrior.

  46. James

    Hey Phil,

    Did you delete the finder preferences (.plist)? Maybe that would clear out the problem.

  47. Kaleberg

    Muys is right. Error code -36 is one of the very old Macintosh operating system numbers. You can get it from a bad disk block, a soft or hard error; you can get it from a flakey or failing network connection; you can get it on an overstressed Firewire daisy chain or from too much USB chaining; you can get it when the disk cache management gets bollixed.

    Usually, if it seems to have gone away, you are fine, but if you get it repeatedly your drive may be on its last legs. Keep your ears open for repeated clicking sounds coming from your drives. If you hear a new sound, it may be time to panic.

  48. Thomas Siefert

    Doug Ellison Said: “Oh – you’re gonna LOVE the Regents St Apple Store in London on the 17th”

    On this level of nerd, I think BA prefers shops where the spotty guy on duty stands behind his counter with his nose deep into the guts of a computer turned inside out. :-)

    We should book a training session in the Regent St. store (it’s only a stone throw from Soho) when BA is here and then ask lots of questions about UNIX.

  49. IRONMANAustralia

    There’s a procedure that always works and solves every problem that ever came up on any Apple equipment:

    1. If you have a wireless mouse skip step 2.
    2. Gripping the mouse firmly pull the mouse cord taught.
    3. Drag and drop the Mac into the bin.
    4. Buy yourself a PC like you should have done in the first place schmuck.

    I’d also like to take this opportunity to apologise to all the young Mac users who were sucked into thinking they were cool for buying a piece of junk that does little but frustrate the hell out of them, while allowing Steve Jobs to mistakenly think he’s some kind of technology guru.

    Those of us who lived through the 80’s, shouldn’t have been so worried about the Ozone Layer, beached whales, and lame stuff like that – and been more concerned about Apple’s marketing tactics – selling trumped-up sub-standard garbage at ludicrous prices.

    If only people had listened to me then and dragged and dropped Steve Jobs into a hole somewhere. I tried to tell them they would regret the kind of world we would leave for future generations, if we didn’t act now!

    So thanks all you old Mac users. Now look and see the irreversible damage you’ve all done to the computer market by giving your money to a company that generates such high levels of technological pollutants.

    And Steve Jobs’ toxic business philosophy has a half-life of over 20 years! So your children, and your children’s children will be left with your socially irresponsible mess.

    Just look at all the Apple-drones running around still believing their Apple Mac is the greatest thing since sliced bread. And it’s worse when they brain-wash their children with this irrational nonsense – just like kids who are raised to believe in fundamentalist religion or racial bigotry.

    It’s so sad.

  50. Tigran Khanzadyan

    Well, I suppose there is no need on being such critical towards any OS – you can achieve the same result on any kind of OS depending on your level of professionalism. There is always a way to solve the problems and it depends on your determination.

    A note on *AVI* files – they are actually archive-directory files and depending on your Finder’s set-up it might take awhile to access it.

    In case of your external drive it might probably be better of you switch of the automatic mapping of the directories there. I suspect that your file was quite big and it was actually trying to map it over there (in .DS_Store) and at some point a hard-drive access time-out occurred.

  51. TheBlackCat

    I love the fact OS X is certified UNIX. Having been in a UNIX world for so many years, it was nice to work with it. Of course, now I’m at a job which is 100% the opposite, Windows. And they look at me funny when I mention anything about UNIX.

    I take it you have never heard of cygwin? You can even use unix commands in the window’s built-in command line. That is one of the (few) advantages of windows, if you want to do something there is usually a way to do it. Mac is built on top of a Unix-like kernel, but it adds so much additional stuff on top while completely locking down the system so it can only be used just the way Apple wants you to use it.

    It seems to take all the disadvantages of Unix (lack of software and hardware support, primarily) but few of the advantages (like freedom, versatility, customization, use of open and transparent software, etc). If you want Unix that badly, you can get it for free (if you don’t like Linux there is OpenBSD, OpenSolaris, and a number of others). I don’t see the point in paying for an expensive, locked-down system when what you really want is Unix. Heck, you can’t even use the Intel Mac Os X in a Virtual Machine, even Microsoft lets you do that (not to mention the many Linux distros that have versions specifically built for that purpose).

  52. What would be a Unix code to move a file (large jpg.) from a ftp site to our hard drive (Mac OS 10.4.11)? The file starts to download and then we get error code -36.

  53. Russ

    /usr/include/asm-generic/errno.h:#define ENAMETOOLONG 36 /* File name too long */

  54. TheBlackCat

    @ Susan: On Linux the command is “wget”, I am not sure if Mac has that or not. I am sure you can download and install it for mac it if isn’t installed by default.

  55. Fred

    I have started noticing this problem too

    I have one Western Digital My Book Pro and 3 of the Western Digital My Book2 Studio drives. All of them are 500 gig. Now I have noticed that there are firmware updates on the WD site as well as software that they say you should have installed, especially if you are using 10.5 leopard
    Im going to start clearing the drives and then updating the firmware and using the WD driver/extensions in my mac os 10.5 and 10.4 computers

    I was getting the error when copying video files off a la cie disk to the My Book Studio a few days ago. Rather than copy 10 or twenty at a time I started to copy one by one. Video files that had reported the error seemed to copy over fine but some files would stop at the same place and wouldnt copy. I had back ups so I just deleted them but it is VERY WORRYING.

    One thing does keep popping up when looking on the internet for this error : Western Digital

    so perhaps the firmware and extensions will fix it all but I didnt see the error reported on the western

    I was starting to think that there were bad sectors on the disk or that it was a permissions problem…..

  56. Fred

    i should say that I was using a powerbookg4 laptop and the lacie was connected via firewire800 to the laptop and the WD drive was pluged into the lacie via FW800 cable

    The lacie drive was formatted on the mac as ms-dos so I could plug it into a windows machine too.
    The WD was formatted for mac,

    Both drives had just 1 partition each

  57. folcrom

    Falling back on the command prompt to do something because the GUI fails, shows that the BA has intelligence. Your unix knowledge shows you grew up with a unix background.

    I find using the command prompt in any OS, whether Windows, Linux, MacOS or whatever, is often useful in solving problems on modern GUI oriented PCs. Never forget the command prompt. It is your friend.

    Having grown up using the old DOS command prompt, gives me a certain perspective, that allows me work around GUI issues. The OS also becomes largely irrelevent, there is always a way around the GUI. You can hack the OS from beneith it’s soft underbelly. Unfortunately kids today have grown up with GUIs and most have no idea that a command prompt even exists. It’s a shame really.


  58. Cory

    Thanks for the information here.. I was going crazy, searched the web for hours looking for a solution… THEN I read the post here about getting error -36 from over stressed firewire… hmm… I have 3 Lacie terabyte drives daisy chained with FW800… I turned off the drive I was not using and BINGO! I was able to start the copy of one drive to the other. (I’m copying 830GB of Data from my main work lacie drive to a second lacie as a mirrored backup.)

    Such a simple fix…

  59. Jason

    I’m having the same error problem…I’m not familiar at all with code, but I though I’d give this a shot because I am very desperate.

    I cd’ed my external, opened a folder called movies inside of there
    and then typed

    cp /Users/neoarchie2001/Desktop/Movie.mp4.

    jasons-computer:/Volumes/External/Television neoarchie2001$ cp /Users/neoarchie2001/Desktop/Movie.mp4.
    usage: cp [-R [-H | -L | -P]] [-f | -i | -n] [-pv] src target
    cp [-R [-H | -L | -P]] [-f | -i | -n] [-pv] src1 … srcN directory
    jason-harrelsons-computer:/Volumes/External/Television neoarchie2001$

    and this is what I get?? I don’t get what’s going on…but drag and drop certainly continues to not work….Can you help???

  60. paulk

    You left out the space between the “mp4” and the following “.”

    try instead, “cp /Users/neoarchie2001/Desktop/Movie.mp4 .”


  61. Jon

    This works great, and the Terminal Help on Mac makes it so you don’t even need to know the commands from heart. Thanks!

  62. thanks, i had an identical problem – i had been google searching with no luck, and i stumbled upon this post, which worked like a charm. thanks!

  63. ciclido

    Hello everyone,

    I have an external hard drive with lots of pictures and I recently tried to rename one of the directories. It gave me the mentioned error -36. However, instead of renaming the directory it left the original intact and then it created a new one with the name that I tried to use to rename the original one. As a result now I have two directories with exactly the same files inside. I have tried everything imaginable including deleting both of them, and it does not let me. It gives me the error code -36 over and over. Then if I tried to rename it again, it creates a new copy of it with the new name.

    Unfortunately, I don’t know UNIX so I would not be able to delete them using a UNIX commands. But I could tried to delete them with your help. Please, help, I beg you… I want to delete all of them.

  64. donkei

    Hi Phil Plait, I’m having the same exact problem now. I can’t copy / move / write any files to my external hard drives. I tried your technique and I could successfully move a file to 1 partition, after which I can freely move files to that partition. However, it still didn’t work when I tried to move a file to a different partition (same hard disk) so I tried the technique again on the 2nd partition.

    The file transfer was terribly slow like USB 1.1 (I’m using FW800) yet after that, I still can’t copy files to the 2nd partition. The error -36 message still pops up and, worse, now I can’t copy files from that partition to my Macintosh HD by dragging. When I tried moving the file from the 2nd partition to my Macintosh HD, the message is ‘Result too large’.

    Can you please help me?

    I’m so desperate now. I’ve tried repairing disk permission, repairing disk, rebuilding disk (DiskWarrior) and even reformatting and restoring my Macintosh HD to no avail.

  65. donkei

    ps : When I tried moving the file from 2nd partition to my Macintosh HD again, the message is now ‘Resource busy’. I tried 5 times in a row and it’s always like that.

  66. g7


    May I know how to open the terminal window?

  67. michni

    I’m newbee to mac. I’ve just unwrapped my first macbook pro. I have a Lacie 1T drive ntfs-formatted and used with winxp to hold my pictures. I want to copy my picturefiles (.NEF, .dng and .jpg-files) to my new macbook. (about 26.000 files). I connect the LaCie-drive through FW800. Finder gives me this very little informative error 36 message. I can actually open some of the files that yields the error. I’ve tried the ditto command but i does seem to stop copying after 1/3 of the files have been copied.
    Does anyone in here have a good suggestion as to what to try next?

    g7: Open Finder, go to Programs, then Tools, and you may see Terminal down there (I don’t know if it is actually named Tools, but must be something like that, my Leopard is in danish.

  68. hd

    Can someone tell me in more detail about how to cp (copy?) and mv (move?) a file from a DVD to my Desktop in this manner (using unix command window).


  69. Media Dude

    Im trying to move files from my desktop to my external but im getting the error code 36 also. i tried terminal and this is what i get

    Macintosh:~ Murda$ prompt%> mv/Users/Murda/Desktop/Logic 8 Serial.rtf/Volumes/Mac Drive/Programs
    -bash: mv/Users/Murda/Desktop/Logic 8 Serial.rtf/Volumes/Mac Drive/Programs: Not a directory

    what am i doing wrong? im trying to move it to my Mac Drive ( usb external, it used to work when i did the drag and drop thing. I can still access files from that drive just not able to copy ) from my desktop

  70. Thank you for saving me $75. I have the same drive and thought it was toast. Unix and Bad Astronomy saved the day! Also for others with this problem: it didn’t work when I tried to mv the file, I had to cp it first. After that everything went back to normal.

  71. z26o

    The console option worked for me. I was getting the same error when trying to move large amounts of data from my internal hard drive to an external drive. All formatted for Mac OS X. Not sure why it works but it does.

  72. Mickey

    This post is probably semi-retired, but just to share what I know to complete the picture.
    I have a new Mac mini Server connected via gigabit LAN to a 1TB NAS storage system. As the NAS ran out of space, I bought new hard disks to replace the existing ones to increase the storage. First, I backed up all the files on the NAS (about 700GB) by copying them to the Mac mini Server’s two 500 GB hard disks. So far so good.

    Then I replaced the NAS hard disks, restarted it, formatted and raid’ed the new disks. Now I have a new 2TB NAS that’s good to go. I proceeded to copy the files from the Mac mini Server back to the NAS. This time, I encountered the infamous Error Code -36 sporadically. Needless to say, I was stumped: I just copied the files from the NAS to the Mac mini, now I can’t copy them back… WTF?! Btw, the NAS is configured as SMB.

    After some googling and piecing together what others had posted, I begin to suspect the problem lies with Mac OS X. In particular, I noticed the Error Code -36 appears on folders that contain the Mac’s most hated dot files, such .DS_Store, ._MyTextFile.txt, etc. To see these files, I went to the Terminal (I’m a programmer for Windows/Unix/Mac) and did a
    $ ls -al
    in the directory. After I manually removed all the dot files, the same folder copied nicely over to the NAS.

    The caveat: dot files are sometimes used as resource forks of Mac files. So which are those that you can delete safely, and which are those you cannot? After some testing, I noticed dot files created by the Finder (to store attributes, such as location, color) shows up as 4096 in the Unix size column. So using the following command
    $ find . (-name ‘._*’ -o -name ‘.DS_Store’ )
    I list out all the dot files and manually went thru them to see which can be safely deleted. It’s painful, but after 10 hours, I finally got most (95%) of my files back into the NAS. The other 5% have dot files as resource forks (> 4096 in size), and I decided to keep them on the Mac mini for good.
    NB: if you just want to remove the .DS_Store files, the following command will do the job
    $ find . (-name ‘.DS_Store’ ) -exec rm {} ;

    In case you’re wondering, my NAS is setup to accept dot files. In fact, some Mac folders in the NAS actually has dot files in it, which means these dot files copied over successfully. However, the other dot files caused problems. I suspect Mac OS X has a bug that prevents it from reading dot files correctly from a Mac HFS+ hard disk.
    I confirm my suspicion, I also tested the following: went to a folder in my Mac mini Server with the offending dot files (those giving -36 error), right-click on the folder and select “Compress Folder” to create a Zip archive. The Finder started zipping and hangs just before completion; after leaving it to run for 15 mins (the folder is < 10MB), I cancelled it. Testing with other problematic folders produced the same result.

    Pretty lame, but apparently Apple is aware of this dot file problem and should fix it in 10.6.3 (according to discussions in Apple forums).

  73. WD

    I thought (and still do) that the prodlem is with my hard drive. I had gone to my friends house to give him some data thats when it started showing this error then the drive just doesnt read on my Mac anymore. It did once and showed the same error. then din’t again

  74. I tried the command line mv command and the command line told me Input/Output error. But I can play the file on my harddrive. – I have the same error if I try to copy the file to somewhere else on my internal harddrive.

    Using OS X 10.6.5 on MBP 15″ moving the file to a WD My Passport via USB. The file in question is a .mts movie file. I can move other .mts movie files which were made with the same camera, at the same time, and are in the same folder to the external hardrive.

  75. Rauf Guliev


    3 years later and Apple didn’t fix this bug. Thanks for your solution!

  76. Sandra

    Hey im going tru the same problem right now the top story of this is exactly what im going tru and ive tried doing what u said bt still wont work tru the terminal…i dont know what to do and im getting frusturated this is my where my movies are at /Users/clumsy_flores and this is where im trying to put them at /Volumes/Time Machine Backups….thats what my WD is called i was able to put movies by dragging or copying them to the WD bt then something happened and i get the error code exactly like yours like i said ive tried doing it like u said bt im not all that familiar with the terminal bt i read carefully what u said to do and i search other methods of help bt still wont work i need help maybe im doing it wrong inputting it on the terminal if u or anyone can plz help…thank u

  77. johnH

    well here it is October 10, 2011, and, after being able to transfer my .avi downloads to a LaCie HD for the past year, about two weeks ago i began getting “error 36” messages with every attempted transfer from my MacMini (OSX 10.6.8) to HD.

    In one way, i am relieved to hear that many others have had a similar problem.
    But evidently the problem is NOT solved, if indeed it occurs at the Apple end of things.

    i thought perhaps it was a flaw occurring during the download stage — even though .avi files played perfectly on the Mini. So I am still struggling to come up with a solution….i’m a novice when it comes to UNIX, I had the impression that the Mini’s HD had to be partitioned to run UNIX — but perhaps that is a mistaken belief.

    The message i receive when i try to transfer a file is:
    “The Finder can’t complete the operation because some data in “*(program title).S03E03.HDTV.XviD-LOL.[VTV].avi” can’t be read or written.
    (Error code -36)

  78. steve

    same problem here with 10.6.8 :(

  79. Kenny

    same problem with Lions, the disk was fine then suddenly this happened. Even reformating the disk multiple times does not fix it. Now I go back to Unix to move the files.


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