Disk Utility can't repair TM backup disk

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Level 1

9 points

Disk Utility can't repair TM backup disk

Hello all

Recently, my external backup disk (a 750 GB WD My Passport) that I use with Time Machine has been acting up. At first, it wouldn't show up on the desktop, but was being recognized in Disk Utility (with the "Time Machine Backup" partition greyed out). After multiple restarts and unplugging/replugging the hard drive, I finally got to be properly recognized, i.e. it showed up on the desktop with the proper Time Machine hard drive icon. So I thought the problem was gone and started a routine backup. However, Time Machine returned an error:

"Unable to complete backup. An error occurred while creating the backup folder."

I search the forums, and followed the advice here: http://web.me.com/pondini/Time_Machine/C10.html

I tried repairing the disk, but DU couldn't repair it:

Verify and Repair volume “Time Machine Backups”

Checking Journaled HFS Plus volume.

Detected a case-sensitive volume.

Checking extents overflow file.

Checking catalog file.

Incorrect number of thread records

Checking multi-linked files.

Checking catalog hierarchy.

Checking extended attributes file.

Checking multi-linked directories.

Checking volume bitmap.

Checking volume information.

Invalid volume file count

(It should be 3991498 instead of 3904049)

Invalid volume directory count

(It should be 678218 instead of 673790)

Invalid volume free block count

(It should be 9588404 instead of 11784378)

Volume header needs minor repair

The volume Time Machine Backups was found corrupt and needs to be repaired.

Volume repair complete.Updating boot support partitions for the volume as required.

Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.

So now I'm still following the advice on the above mentioned page by posting on here. Any help at all would be greatly appreciated. I am using a 2010 15in 2.66 i7 MBP, if that makes a difference, although my guess is the problem's with the harddrive itself. I think there may have been one time about a month ago when Time Machine stopped responding (or something like that) which forced me to pull out the harddrive, possibly corrupting the data. But I'm not sure, and I do recall making at least one successful backup after that. Well, actually TM confirms this: "Latest successful backup: 5/27/11 at 11:51 PM". So I have no idea what's going on. Again, any help would be appreciated.

Mac OS X (10.6.7)

Posted on Jun 6, 2011 8:27 AM

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Answer 1

T0mdaB0mb Author

Level 1

9 points

Jun 6, 2011 8:44 AM in response to T0mdaB0mb

It might be worthwhile noting that, apart from with Time Machine, the disk appears be working fine. That is, (as mentioned) it appears on the desktop and Finder sidebar with proper TM icon, I can access the files, I can write to it, I can create folders (which Time Machine seems to find itself unable to do), etc. That's why I tohught the problem was fixed at first (evidently it's not). It's only when I do "Back Up Now" on the TM icon on the menubar, that the error came up. And of course the multiple errors thrown out by disk utility... Perhaps the fact that it's only not working with Time Machine can shed some light as to which parts of the disk are corrupted?

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Answer 2

Jun 21, 2011 8:06 AM in response to T0mdaB0mb

Hope this helps...

Mac OS X: fsck reports benign errors when journaling is turned on

http://support.apple.com/kb/TS2028?viewlocale=en_US

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Answer 3

Pondini

Level 8

38,863 points

Jun 21, 2011 4:03 PM in response to T0mdaB0mb

You can't tell what's corrupted or where. Time Machine backups have a very complex structure, all linked together. So, you can often do new backups, or restore individual items, or even entire backups, as long as you don't stumble over the damage.

There's a chance a heavy-duty 3rd-party disk repair app, such as Disk Warrior, can repair them. It's about $100, and probably a good investment for the future, but there's no guarantee it can fix them.

If not, or if you don't want to spend the money, your only option is to erase the disk and let Time Machine start fresh.

It sounds like you may have other data on it; if that's in the same partition, that's not a good idea. This is a good time to copy the data off, erase the disk, and make 2 (or more) partitions on it, so Time Machine has its own, exclusive space. See #3 in Time Machine - Frequently Asked Questions for details and instructions.

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Answer 4

Linc Davis

Level 10

209,541 points

Jun 21, 2011 4:06 PM in response to JohnBradshaw

Hope this helps...

"This document applies to Mac OS X 10.3.9 or earlier."

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Answer 5

T0mdaB0mb Author

Level 1

9 points

Jun 21, 2011 4:56 PM in response to T0mdaB0mb

Thanks everyone for your replies.

I've managed to fix the problem already, and I realize I probably should have followed up on here. I simply reran Disk Repair and it managed to repair it the second time. Don't know what was wrong the first time, but Time Machine is working fine now.

My advice to people getting errors running disk repair would be to try running it again, maybe even a couple times. Pondini, perhaps you could consider adding that to your guide on fixing Time Machine problems? Don't get me wrong, I found it very useful and informative, and I'm sure plenty of people would agree with me.

And thanks for the advice on partitioning the backup disk. It never occured to me to do that.

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Answer 6

Pondini

Level 8

38,863 points

Jun 21, 2011 5:10 PM in response to T0mdaB0mb

T0mdaB0mb wrote:

. . .

Pondini, perhaps you could consider adding that to your guide on fixing Time Machine problems?

Good point! Will do, and thanks. 🙂

UPDATE: I thought it was odd that I'd missed that, and I hadn't; it is mentioned in the paragraph in blue. I guess I need to make it more obvious?

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Answer 7

T0mdaB0mb Author

Level 1

9 points

Jun 21, 2011 5:56 PM in response to Pondini

Ah I see, in A5, you do mention that in the purple (or is it blue on your screen?) text under the blue box, but that's the only place I found reference to it. I suppose it could be a bit more obvious, maybe have it in red, because purple wouldn't, and didn't, strike me as what I should do if there's still errors. The thing is, I followed the link to A5 from C10 (my specific problem), and when my disk repair failed the first time, I scrolled immediately down to the red box, where it had no mention of running disk repair again, since it assumes we would have gone throught all of A5 from top to bottom. Which I didn't, since I rather foolishly assumed I knew how disk repairs work. My suggestion would be to include (just as a sort of reminder) the tip about running disk repair again multiple times in the pink/red box on the bottom. That's just based on my experience.

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Answer 8

Pondini

Level 8

38,863 points

Jun 21, 2011 6:32 PM in response to T0mdaB0mb

Yeah, there's a lot of stuff there, for all the various circumstances. It's hard to emphasise everything!

I'll either move it to the red box or make a separate one, or something.

Thanks for the suggestions.

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Answer 9

Pondini

Level 8

38,863 points

Jun 21, 2011 7:58 PM in response to T0mdaB0mb

Revised #A5 and (of course) added some stuff & reorganized.

See if it's better, worse, or ?

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Answer 10

T0mdaB0mb Author

Level 1

9 points

Jun 22, 2011 4:50 AM in response to Pondini

Yeah, I think it's better! I suppose you could have the bit about rerunning disk repair in both the green box and the pink, but the way it is now is fine. Glad you found my suggestions useful.

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Answer 11

Jun 22, 2011 7:33 AM in response to Linc Davis

Linc Davis wrote:

Hope this helps...

"This document applies to Mac OS X 10.3.9 or earlier."

::ahem:: 😉

Mac OS X: About file system journaling

http://support.apple.com/kb/HT2355

You may see certain harmless "error" messages when journaling is turned on. To learn about these, see "Mac OS X: fsck Reports Benign Error Messages When Journaling is Active".

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Answer 12

Linc Davis

Level 10

209,541 points

Jun 22, 2011 8:28 AM in response to JohnBradshaw

That's a link to the other article, which only applies to 10.3.9 or earlier. Otherwise there are no "harmless" error messages from repairing a volume header.

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