Time Machine: UUID of Disk Changed
If you clone a volume that you backup with Time Machine, its UUID will change and Time Machine will no longer be able to make backups of it. However, it won’t tell you directly what the problem is. Rather, you will find entries like the following in
backupd Backup failed with error: 12 backupd Error (12): Link of previous volume failed for macosx.
If you want to continue to backup to the same volume in your Time Machine backup database, the following script allows you to change the UUID of the existing backups, leading Time Machine to backup as if the volume’s UUID had never changed.
Starting from OS X Lion 10.7, there is a nifty new command line utility called
tmutil, which takes care of the task previously accomplished by the script described below. Here is an example of how to use
tmutil to associate a new disk with an existing backup.
Mac OS X 10.6 Snow Leopard has ACLs enabled by default and therefore ships without the
fsaclctl command line tool that we need to temporarily turn off ACLs. You may try to grab it from a Leopard DVD:
Use this at your own risk!
./timemachine-setuuid.sh "Backup of MyMac" "Macintosh HD" Using Time Machine volume "/Volumes/Backup of MyMac" with backup database located at "/Volumes/Backup of MyMac/Backups.backupdb/MyMac" UUID of volume "Macintosh HD" will be set to "394FBC68-AA00-3556-81B5-D61F5BFA27ED" Done
And here’s the script.
Save the above code to a file called e.g.
timemachine-setuuid.sh and make that file executable by issuing
chmod +x "timemachine-setuuid.sh"