Supplemental Update broke Time Machine

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Level 1

6 points

Supplemental Update broke Time Machine

We have just upgraded multiple Mac clients and a Mac Mini Server with the High Sierra 10.13.2 Supplemental Update at https://support.apple.com/en-au/HT208397. All devices were previously up to date.

After rebooting, all the clients are exhibiting the same error when attempting a time machine backup: "The network backup disk does not support the required capabilities". The console log shows backupd complaining of "/Volumes/Time Machine Backup does not support required Time Machine capabilities" and just prior to that is a kernel log of "smbfs_vnop_ioctl: TM Read - attributes 0x14 reconnTO 0 Qos 0x0"

The mountpoint is still an HFS+ file system shared as a Time Machine backup destination and all other file share services are operating nominally.

Does anyone have a handle on the possible causes and mitigations of this error?

Posted on Jan 15, 2018 7:23 PM

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Answer 1

Best reply

inopinatus Author

Level 1

6 points

Feb 2, 2018 3:33 PM in response to inopinatus

This was a permissions problem. Why the Supplemental Update changed permissions is not clear, but the file

.com.apple.timemachine.supported

was no longer readable by users. In our case the fix was therefore:

sudo chmod 644 '/Volumes/Bulk#2/Time Machine Backups/.com.apple.timemachine.supported'

after which clients proceeded normally.

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Answer 2

Fai2

Level 1

14 points

Mar 22, 2018 11:50 AM in response to The Skeptic

However turning off SMB is undesirable, since AFP has been deprecated for some time is likely to disappear altogether.

Our network backups did take a dive with the 10.13.3 Supplemental Update (the server is on Sierra 10.12.6). Applying the chmod 644 command (from Inopinatus above) fixed it, so big thanks for that.

I had to go to the man chmod page in Terminal to learn this, but applying the 644 mode makes the referenced invisible file readable by anyone and writable by the owner only.

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Answer 3

Mar 22, 2018 2:32 PM in response to Fai2

I did try the chmod 644 as suggested above, but got no love. Maybe after the next update, I'll try turning SMB back on and doing chmod 644 again. So far, it's been working perfectly over AFP. Hopefully Apple figures out what's wrong and fixes it.

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Answer 4

Feb 26, 2018 5:45 PM in response to inopinatus

Turning off the SMB sharing did the trick for me. Seems 10.13.3 doesn't like backing up over SMB.

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