Time Machine – Failing to backup (Error 49)

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Level 1

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Time Machine – Failing to backup (Error 49)

For quite some time I've been having issues with Time Machine. Even after buying a new backup drive the issues persist. Strangely, a month worth of backups has passed, and only now the issues have started.

After initiating a backup it fails instantly, without backing up a single file.

When trying to initiate a backup, the following happens:

Time Machine Error Log

The drive is GUID Partitioned, macOS Extended Journaled. (I have tried MBR & Apple too, none work).

Running Mojave (10.14.6). Also, no .inProgress file is present, the iMac folder is empty. Removing the com.apple.TimeMachine.plist file also doesn't fix the issue.

When restarting my Mac, or performing a macOS system software update, the mac instantly reverts to the latest backup available, thus resulting in data loss. It also doesn't complete the update, it is stuck on the same OS version as before shutting down. Usually after attempting to update for a second time, it completes and upgrades, but doesn't retrieve my lost data.

iMac Line (2012 and Later)

Posted on Aug 12, 2019 6:54 AM

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Answer 1

Best reply

John Galt

Level 10

141,210 points

Aug 12, 2019 10:33 AM in response to Casperster18

The source volume (meaning, your iMac's usual startup disk—not the Time Machine backup drive) is operating in a state of failure.

Most likely, it will require replacement. Until you can get that accomplished, boot macOS Recovery, and at the macOS Utilities screen select Disk Utility and use its First Aid function to repair that disk: Repair a disk using Disk Utility on Mac - Apple Support.

Any such repair is likely to be temporary in nature, meaning the problem is likely to occur again, but the "repair" may result in the ability to use your Mac normally—and more importantly, create a more recent backup.

Contact Support to have Apple evaluate that Mac and provide repair options for your consideration. When you replace your Mac's startup disk, you will need to restore its content from that Time Machine backup.

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Answer 2

Casperster18 Author

Level 1

11 points

Aug 12, 2019 10:54 PM in response to John Galt

After performing First Aid on the Fusion Drive and restarting my Mac, again a few files were lost due to restarting. However, the Disk Aid mentioned all volumes appeared OK, and no major issues were found.

The only error it found was:

error: sm: sm_free_count (262913) is not valid (262912) (sm_dev 0)

I immediately performed a regular first Time Machine backup overnight, and woke up to a finished backup this morning. Attached the log, which shows the attribute errors are still present:

success_backup_sample

Thankyou for your help and advice so far. It's very much appreciated.

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Time Machine – Failing to backup (Error 49)

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