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I have an airport extreme with a drive connected, and use it for backing up snow leopard macs. I have an occasional problem with one of them that says "the backup disk image ... is already in use" and it fails to backup.

Any ideas?

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What worked for me in the end was to "disconnect all users" from the Airport Utility - and then unplug/plugin the drive again (remount it) - it was then able to backup successfully.

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I think it's just a temporary solution as I still have the error message from time to time :( – Enrico Susatyo Sep 5 '11 at 23:11
disconnect all users isn't available in the latest version (6), but you can download 5.6 from apple - – arolson101 Jul 6 '12 at 0:37
more info on this procedure at – mac Dec 19 '12 at 22:12

There isn't an .InProgress file still on the drive is there? That can cause problems. Just delete it to get the backup working again.

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This is a pretty good suggestion; upvoted. – Alexander Burke Mar 17 '10 at 14:38

The disconnect, power off/on works, but only temporarily. I think for me it hoses up if I close my macbook pro lid while its trying to backup.

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FWIW - this seems to be solved now, post a few updates to OS-X – Michael Neale Nov 17 '10 at 22:29
does not seem to be fixed in 10.7.1 – Enrico Susatyo Sep 5 '11 at 23:11

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