Hard Drive to Hard Drive transfer fail: error 36?
October 26, 2010 3:53 AM   Subscribe

I have two of these Seagate 1TB external hard drives. Both formatted the same way: Mac OS Extended, GUID partition table. One has 400GB stored on it. When I drag and drop from one external hard drive to the other, after a while (anywhere around 8GB and up) I get an error 36 message - says I cannot read/write file. The lady on the phone for Seagate support says it's because you can't drag and drop large amounts of data via USB: in other words, it's not the drive's fault. Really?

Mac OSX 10.5.8.
61GB free space on own hard drive
The 400GB I'm trying to move has a lot of nested folders in it (it's a collection separate photo/film shoots).
I'm not using my computer for anything else while it's transferring files.
The files will transfer individually.
Error 36 message: "The Finder cannot complete the operation because some data in "example.mov" could not be read or written. (Error code -36)"

Oh, and some background:
I formatted the drives (let's call them drive A and B), then copied the info from two other drives (say, C and D) onto drive A. Then, when I tried to copy from drive A to the empty drive B, I started seeing error 36. I checked out drive A on disk utility - had problems. See image. So, I copied all info from A to B (dragging and dropping the info as the error messages popped up). Then reformatted A. Then I found out that B also had errors, so I repaired it. Now disk utility says that neither drives have errors. I don't really know how to move forward in problem solving here. Could it be my computer that's the problem?
posted by omnigut to Computers & Internet (20 answers total) 1 user marked this as a favorite
If I copied info onto a damaged drive (A), and then copied it off onto another damaged drive (B), then reformatted A and copied the information back onto it from B, despite A now not having errors, could it be that the files themselves are corrupted? They still play in quicktime. Is their invisible ninja stuff causing problems?
posted by omnigut at 3:55 AM on October 26, 2010

I have a Seagate freeagent drive (1.5Tb) which works fine under OSX. When I first got it, I tried using it under a linux system (OpenWRT) and it was a nightmare. The freeagent enclosure had enough smarts to sleep, but not enough to wake up.

I don't know if this is your problem and, like I said, OSX wasn't the problem for me. That said, I'd try doing your copy with rsync (or even mv or cp) instead of finder.

Actually, I've just checked and my one is "Apple Partition Map", with a MacOS journaled filesystem. Perhaps mimicing that would be the go...
posted by pompomtom at 4:17 AM on October 26, 2010

Sorry, I should say: AP M and HFS+ journaled FS.
posted by pompomtom at 5:13 AM on October 26, 2010


If this is your problem, it seems an upgrade to 10.6.3 or later will fix it.
posted by Biru at 5:14 AM on October 26, 2010

Biru, it seems that's a Windows to Mac problem (or mac to windows, or whatever) - both my drives are mac formatted. Also, I think I'd have to pay to upgrade to 10.6. However, if getting snow leopard would fix it, and speed stuff up, then so be it...

Pompomtom, I'm not at home, but I don't think disk utility offers the chance to reformat a drive as an APM and HFS+ journaled fs. Or is it that an APM is what disk utility will automatically do? (Okay, I'm a little confused :) )

When I get home I'll reformat Drive A to be "journaled", as above, copy all the info onto it, then reformat Drive B to be journaled, and then copy the info back... (groan)
posted by omnigut at 5:25 AM on October 26, 2010

Question: is there any negative aspect to a "journaled" drive?
posted by omnigut at 5:43 AM on October 26, 2010

Sorry - let me rephrase: I thought journaling was only for start up drives, not data storage drives. No?
posted by omnigut at 5:45 AM on October 26, 2010

Journaling (wiki) isn't a bad idea for almost all filesystems; the only reason not to use it would be if you're so performance-sensitive that the overhead is unacceptable. I actually like it (a lot) for external drives, since it aids in the recovery if you suddenly unplug the drive -- at least in theory. I'm not really that up to date on OS X's journaling implementation.

Anyway, the first thing I would do is run Disk First Aid Disk Utility on the offending drives. Be prepared for it to take a few hours ... but it might turn up something. At the very least it is unlikely to hurt; although you should of course have backups of anything that is stored on these drives, since they are at the moment not trustworthy.

It's entirely possible that there's some defect in the USB controller on these drives, but I've never had any problem exactly like you describe ... although I have had other issues involving external drives connected via USB. (The issue I have is after being mounted for a while, the drives will become un-writable. Disk Utility's Repair function seems to solve this, for a while.)
posted by Kadin2048 at 6:51 AM on October 26, 2010

Okay, I've reformatted drive A to a journaled APM, and am now copying the data from B to A. When that's finished, I'll reformat B, and copy all the data back. Hello 8 hours of dragging fricking files :(
posted by omnigut at 7:34 AM on October 26, 2010

You don't have to sit there while it copies.. :)
posted by devnull at 8:28 AM on October 26, 2010

Hello 8 hours of dragging fricking files :(

I would really recommend using rsync instead of drag and dropping by hand. As the seagate tech implied, USB drives are not perfectly stable over long periods of heavy use; this jibes with my personal experience, especially under OSX. With rsync, you can restart an interrupted copy automatically, and it will handle figuring out which files still need to be copied over.

Open a terminal window and type "df -h"

bash-3.2$ df -h
Filesystem Size Used Avail Capacity Mounted on
/dev/disk1s1 1.8Ti 790Gi 1.0Ti 43% /Volumes/My Book2
/dev/disk1s2 1.8Ti 790Gi 1.0Ti 43% /Volumes/My Book1

Your two external drives will be mounted under /Volumes with a name automatically generated by the system based on the volume name of the device. If the two drives are identical, it may take a little inspection on your part to determine which one is which. Once you have,

rsync -avz /Volumes/source-drive-path /Volumes/target-drive-path

Now, if/when the USB drive hiccups and disconnects, you can just issue the same command again, and the copy process will proceed from where it left off last.

posted by nomisxid at 8:29 AM on October 26, 2010 [1 favorite]

nomisxid: That command will create a folder in the destination drive named after the source drive. Not sure if that was the goal or not.

Assuming the destination drive is clean, I'd suggest "rsync /Volumes/drive1/ /Volumes/drive2". (The trailing slash after drive1 tells rsync "copy the contents of this directory" rather than "copy the directory" itself.)

The easy way of doing this on OS X is to open a Terminal window, type "rsync -avz" and space, drag the first drive's from the Desktop into the window (which types the path to it automagically), hit "/" and space, then drag the second drive's icon into the window, and press Return.

And I just wanted to underline the absolute importance of using the -a switch for archive mode. If you don't do this, you'll blow away all the modification / creation times (among other things) on your files. Which is unpleasant. Not that I've done that or anything.

I'm not sure what's happened with OS X's USB support; it seems like it used to be rock-solid, but in the past few years I've had a lot of problems with it as drives have gotten larger.
posted by Kadin2048 at 9:52 AM on October 26, 2010 [2 favorites]

Just chiming in to say that Kadin2k has it exactly right.
posted by Lame_username at 10:32 AM on October 26, 2010

Thanks all. Sorry, though, I didn't get the terminal advice (I'm not much of a code person). However, it seems that this code is to help me get around the drives' instability. However, this doesn't seem to fix the problem with the drives – they can crash after transferring as little as 2GB, when I've only dragged a 10GB folder across. I'm pretty close to getting all the info put on the newly journaled drive (drive A). Will reformat B when it's done, transfer all the info back... watch this highly tedious space...
posted by omnigut at 11:05 AM on October 26, 2010

Well.. when you consider there are a variety of different factors that might effect USB file transfer stability:

1.) What OS (and level of OS patches you are using)
2.) Drivers and background programs running?
3.) Firmware and revision of controller-board inside the drives enclosure
4.) Motherboard chipset (specifically the "southbridge")

It's not entirely false for the Seagate rep to say "it's not the drives". Of course you should do due diligence to test/diagnose the drives... but the drives themselves are only 1 of a variety of factors that might influence large file transfers over USB.

In the past when I've had problems like this.. I tried to isolate the problem by doing things like:

1.) plug each USB drive into a different USB controller (example: plug 1 drive into your onboard USB ports.. and plug the 2nd drive into a USB PCI Card)

2.) Only plug 1 drive in at a time.. (migrate files to local hard drive, then unplug Drive1 and plug in Drive2 to migrate files from local hard drive to Drive2. Sure, this isn't ideal.. but it works)

My suspicion in cases like yours has always been that massive file transfers to 2 different external drives all has to be managed by your internal USB chip ("Southbridge").. and depending on manufacturer and chipset driver, you may be pushing/exceeding it's limits.

Other things I might suggest:

1.) Upgrade your OS

2.) Find someone else with the exact same hardware/OS-level as you have now.. and ask them to test -- see if they get the same problems with your drives.

3.) ?
posted by jmnugent at 11:24 AM on October 26, 2010

Hey JMN,

From part one:
1.) Mac OSX 10.5.8 (patches?)
2.) Driver? Dunno. But the only other programs running are Google Chrome and Text Edit.
3.) and 4.) I have no idea. It's whatever came with my macbook.

part two:
1. I don't have any choice where I plug them in (my macbook only has two usb ports)
2. This might work, but I'd like to know what the problem is, not put on a bandaid

1. Snow Leopard? Could do, but wouldn't want to do this for no reason.
2. Dunno how probable this is :)
posted by omnigut at 11:36 AM on October 26, 2010

If all you are doing is copying the contents of A directly to B, why not let something like SuperDuper handle it for you?
posted by caution live frogs at 12:52 PM on October 26, 2010

Hey Omnigut.... If you click on the Apple, then "About this Mac".. and go to the "More Info" button... there is a ton of hardware info in there. I don't have access to a Mac at the moment.. but could you dig through there and see if it tells you what Northbridge/Southbridge (or USB Controller) your Mac uses?.... (or at the very least, what make/model Macbook you have) Maybe this would help us Google search to see if other users have similar issues.
posted by jmnugent at 3:27 PM on October 26, 2010

Okay, having the two hard drives "journaled" didn't work. It crashed after 130GB had transferred. Now using SuperDuper. Hopefully that'll be better...
posted by omnigut at 4:12 AM on October 27, 2010

SuperDuper does what is says on the tin. caution live frogs – you've just earned best answer :) THANKS!
posted by omnigut at 10:34 AM on October 27, 2010

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