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10.5: Repair Time Machine after logic board changes
Authored by: barrysharp on Feb 01, '08 07:40:30PM

This HINT, although correct in its implementation, is unnecessary for the situation the Author states.

If you attempt to backup after the MAC address has been changed the TM backup will indeed fail and report it cannot found the TM backup volume. This is because the hidden file with the name of the MAC address (minus the colons) does not match the new MAC address.

All that is required here is to goto TM Pref panel and click on the "Change Disk..." button and reselect the TM backup disk and then manually force a backup via the Dock's TM icon "Back Up Now". The backup will now run and the new MAC address will be created as a hidden file alongside the old one. You can use sudo to remove this old one.

TM backup will proceed as it would have normally done without the MAC address change and without a deep traversal of all volumes that have not been excluded (as one person above experienced).

So as much as I applaud this HINT I have to say it's not necessary for dealing with a MAC address changing. However, it does alert people to the importance of the MAC address as it's used by Time Machine.

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Regards... Barry Sharp



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10.5: Repair Time Machine after logic board changes
Authored by: fygoat on Feb 01, '08 07:52:44PM

In my experience, however, following a logic board/MAC address change Time Machine will refuse to recognise the previous backups as belonging to the current system. After re-selecting the backup drive, it will just start a new backup set.

This hint allowed me to continue backing up in the same 'timeline' as the previous backup data. The only problem is that it seems to have forced a deep traversal and copied over most of the file system again.



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10.5: Repair Time Machine after logic board changes
Authored by: barrysharp on Feb 01, '08 09:52:58PM

Not so. It will recognise the earlier snapshots. Why would it not if the only association between the computer and TM is the MAC address. It simply does not make sense for it to be otherwise.

Have you verified using the TM browser that you cannot view or access the earlier snapshots - that is, the ones taken under the old MAC address ?

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Regards... Barry Sharp



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10.5: Repair Time Machine after logic board changes
Authored by: fygoat on Feb 02, '08 07:31:35AM

Yes, I've had the same problem quite a few times. Went through 3 replacement machines of identical configuration, each time Time Machine would initially report 'Backup Failed', saying it couldn't find the backup volume.

Re-selecting the backup drive would enable backups to proceed but Time Machine would create a new, separate backup instead of continuing on from the previous backup data.



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10.5: Repair Time Machine after logic board changes
Authored by: barrysharp on Feb 02, '08 11:59:54AM

Yep - I ran a few tests on this scenario and you're correct. I was not able to figure out just how to fake TM into continuing on from where it was. It does always make a new FULL backup. :( Bummer.

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Regards... Barry Sharp



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10.5: Repair Time Machine after logic board changes
Authored by: barrysharp on Feb 01, '08 09:58:35PM

TM will make a full backup if it cannot trust the backup volume's TM management data. I suspect if you used the HINT as posted here that what you did was insufficient to convince TM that things were as they should be. Hence TM will protect user by doing a full backup as a safety precaution.

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Regards... Barry Sharp



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10.5: Repair Time Machine after logic board changes
Authored by: DylanMuir on May 20, '08 12:46:54AM

I followed the process outlined in this hint, then also set "use this disk for backup" in the time machine preferences. Now, new backups appear to be going to the right place (ie, continuing the old backup store), but in "time machine view", it appears as though nothing is backed up. No mater which folder in the finder I'm looking at when I enter time machine, the view switches to the "computer" (ie top-most level) view.

If I use 'tms', files are shown as existing only in the latest snapshot.

Any ideas? I'm concerned that there might be a deeper problem, and just starting a backup from scratch may not fix it. Ideally I'd like to have my backup history back...

DRM



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