Can duplicate partition UUIDs cause trouble? And, can partition UUIDs be changed?

[robbie-hatley]

I used “Aomei Partition Assistant”, booted from a USB stick, to make backup clones of my “/”, “/boot/efi”, and “/home” partitions. And that worked fine. But wow, when that program says “clone”, it means verbatim clone, including UUIDs. So now the UUIDs of my root, boot, and home partitions are duplicated in my backup copies.

The system was getting confused and mounted the wrong partitions to “/”, “/boot/efi”, and “/home” on next startup. So I had to change the “UUID=xxxxxx” in several fstab lines to “PARTUUID=xxxxxx” instead (the PARTUUIDs were not duplicated), and that fixed that problem.

So, I have two questions:

1. Can such duplicate partition UUIDs cause problems (other than causing wrong partitions to be mounted at startup)?

2. Can UUIDs of partitions be changed? If so, how?

[megavolt]

Hello @robbie-hatley

@robbie-hatley

Can such duplicate partition UUIDs cause problems (other than causing wrong partitions to be mounted at startup)?

Yes

@robbie-hatley

Can UUIDs of partitions be changed? If so, how?

Yes, example:

Same identification number for two partitions

There are rare situations where partitions have the same UUID. In the case generate a new one: Check if it has the correct UUID: sudo blkid /dev/sdb2 Unmount this partition: sudo umount /dev/sdb2 Generate a new UUID: sudo tune2fs -U random /dev/sdb2 Check again, if the UUID has been changed: sudo blkid /dev/sdb2 That should work. Now you can mount it with the new UUID.

[robbie-hatley]

Thanks. That worked, at least for 2 of the 4 affected partitions. The third was FAT32, so tune2fs won’t work on it, but I found another way. And the fourth is a clone of my Windows C drive, and that one actually needs to have a duplicate UUID due to Microsoft license issues.

I also set all the backups to “noauto” in fstab, so when I plug-in that device they shouldn’t auto-mount. To mount them manually, I need only launch Gnome Disk Manager and punch the “play” buttons.