Comments on: Time Machine and a new motherboard

By: Michael

Michael — Tue, 31 Aug 2010 22:09:34 +0000

Seems like 10.6.4, at least, has this problem nipped. Time Machine detected that the machine had the same name but that the back up was from a different computer. I could click “Reuse backup” and it carried on as usual… it only backed up a few gig not the whole hard drive.

By: Nicola

Nicola — Fri, 02 Jul 2010 22:54:26 +0000

It worked!!! you guys just saved me!!!!

By: Caleb A.

Caleb A. — Tue, 11 Aug 2009 19:31:55 +0000

OK, so the link didn’t make it through the system that time. Here’s another try for that “official” MacOSXHints How-To: http://www.macosxhints.com/article.php?story=20080128003716101

By: Caleb A.

Caleb A. — Tue, 11 Aug 2009 19:22:01 +0000

Here’s the “official” How-To over on MacOSXHints.com , which includes how to get around the ACL issue without completely getting rid of them. Full instruction set, verified by the author before posting.

By: Erik

Erik — Sat, 18 Jul 2009 10:39:05 +0000

Thanks for that summary Mark.

By: MartinB

MartinB — Sun, 21 Jun 2009 14:54:30 +0000

I thought I had succeded in this. The new backup did not create a « MyMac 2 » volume, but it started backing up the whole system (in my case 60GB), which beats the purpose. Any cues ?

By: Mark

Mark — Mon, 01 Jun 2009 00:25:09 +0000

This worked perfectly after my logic board was replaced. So to summarise:

chmod -N Backups.backupdb
cd Backups.backupdb
chmod -N [Whatever your machine name is. This will be what the directory is called]

Then you:

sudo xattr -w com.apple.backupd.BackupMachineAddress [Enter your MAC address - the Ethernet one] [Whatever your machine name is. This will be what the directory is called]

By: William

William — Thu, 19 Mar 2009 21:02:48 +0000

Great to have this information – a pity that Apple does not seem to tell people after their logic boards have been replaced that this will be a problem… Took hours to figure out something was amiss and then some more time to track down the answers here, at http://discussions.apple.com/thread.jspa?messageID=6179417 and http://www.macosxhints.com/article.php?story=20080128003716101

Just a note to point out that in doing the xattr -w and chmod +a commands you probably need to use sudo to get the appropriate permissions (the first time I ran through these steps nothing changed because of not doing that, although there were no errors reported).

Now I just need to wait for the backup to complete. As others have posted it seems to take much longer than usual.

By: Peter

Peter — Sun, 20 Jul 2008 05:27:58 +0000

Excellent entry. For some reason, time machine stopped recognizing my previous backups after I repaired my disk. Turns out, the MAC address changed (not sure why), but your advise did the trick.

Thanks a lot.

By: Adam

Adam — Sat, 28 Jun 2008 19:38:57 +0000

Awesome. Saved my bacon. (Where by “bacon” I mean “the practical use of my backup drive.”)