Time Machine corrupted backup? No it's fine but you can't use it anymore!

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29 points

Time Machine corrupted backup? No it's fine but you can't use it anymore!

Hi,

this is the second time I get a corrupted Time Machine backup in two months.

Or at least it seems so. In facts the sparsboundle image is not corrupted as well since I verify it both in DiskUtility and via terminal with fsck_hfs.

Time Machine still wants to create a new backup.

This article on Apple support needs to be updated, cause it doesn't explain what to do in case the verify via DiskUtility of the sparseboundle disk image went out fine.

I would like to understand what the heck do I have to do get back to work my old and not corrupted Time Machine backup.

Thanks for any help.

iMac, Mac OS X (10.6.7)

Posted on May 15, 2011 9:39 AM

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Answer 1

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Rayced Author

Level 1

29 points

May 15, 2011 4:15 PM in response to Rayced

Found it.

Had to modify two files in the sparseboundle image.

unset the uchg flag on file token using the command: chflags nouchg /Volumes/pathToSparseboundleimagefile/token
change the com.apple.TimeMachine.MachineID.plist. In this file are stored infos to pair the sparseboundle image to the computer you are using Time Machine on. In particular there were two addons which prevented to pair again the sparsboundle image to the system. Had to remove the entire entry: RecoveryBackupDeclinedDate and then modify the entry VerificationState which was set to 2 when the backup appeared corrupted, I set it back to 1 which is the value for a working backup disk image.

After this I could start the process of letting Time Machine verify the backup too (just to be sure it is fine) via ALT cliking on the menubar Time Machine icon and choosing "verify backup" from the menu.

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Answer 2

Dec 24, 2013 12:30 AM in response to Rayced

This helped me once, sadly not the 2nd time. Though maybe that also had to do with the fact that the sparsebundle image had a datestamp in its name, rather than simply being called hostname.sparsebundle .

That didn't occur to me until after I started a whole new backup, throwing away years of archives that hopefully I'll never miss.

Curiously, I've NEVER had this kind of issue until I moved and reconfigured my TimeCapsule to act as a simple ethernet switch rather than as my wifi router. Would the increased bandwidth have something to do with the image getting "corrupted"?

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Answer 3

Jawelm

Level 1

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Mar 21, 2014 5:26 AM in response to Rayced

I have found a relatively simple work around to this problem that has been working for me. When computers do not work properly, I have always found the best thing to do is reboot. Therefore when Time Machine is not working, I reboot my WD MyCloud drive.

In Safari log onto WD MyCloud using the IP address ###.###.#.#/UI/
>Settings
>Utilities
>Device Maintenance
>Device Power: Reboot and select OK

This takes several minutes to execute. Afterward I relog on to the server.

in Finder
>Go
>Connect to Server and select WDMyCloud and select user account. I generally just sign in to my main account

I am not sure this last step is necessary. I can then start a new backup with Time Machine, which is the latest incremental backup and not a complete new backup. All my backup history is perserved.

It may also be possible to just power off the WD MyCloud drive, but I have not tested this.

I am using a Macbook Pro and only have the problem after I take my computer on the road to work at another site for the day. The problem appears to be caused when Time Machine is looking for the drive and can not find it. Solving the problem may take both Apple and WD working together to fix.

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