Is it possible to recover the serial number of a hard drive used for Time Machine?

According to Apple's help pages a fingerprint of the time machine backup hard drive is stored for security reasons.

I wonder, is there any way to recover serial or some other unique ID about the drive so that I know if the broken drive in front of me is indeed the one with my old time machine backup?

Solution 1:

Unfortunately you cannot recover the drive's serial number that way.

As mentioned in the help page you link, the identity is used to check amongst other things whether or not you have erased/reformatted the backup disk. Therefore the identity is not something that identifies the physical disk, but rather the file system that is put on it.

In actuality the identity is simply UUIDs that are stored in a plist file on the host computer. When you format for example a HFS+ volume, a persistent, unique UUID is written to it. It is this number that is used as the identity.

This means that if you replace the disk with something else, if you reformat the drive, if you erase the drive, or similar - the computer can detect it as a different disk.

Your only hope now is if the broken drive you have is not so broken that you can't read the HFS+ persistent UUID from it. On a non-broken disk, you'll be able to read it out by running: