I use Time Machine to back up both my MacBook Pro and a portable USB drive containing my iPhoto library that's sometimes connected to it.
Over the years, the external Photos drive has died and been replaced twice, and (my fault) I've failed to properly re-associate the new drive with the old backup (if that's even possible for external drives... never tried).
The upshot of this is that many of my Time Machine snapshots contain two or three snapshot volumes (to use the terminology defined in the
tmutil manpage): one for my MBP, one for my original Photos drive, one for its replacement, and one for its replacement:
I don't really want to keep around the snapshots of the previous incarnations of the drive (the Photos and Photos 1 folders, in this case), as presumably they're taking up nearly 200G between them, which I could be putting to much better use.
But it's not clear how to safely delete them. There's no way from within the Time Machine application to delete volume snapshots, and Apple's tech note says (emphasis mine):
You can use the Finder to move, copy, or delete the Backups.backupdb folder on your Time Machine backup disk as you would other folders. You can also delete folders within the Backups.backupdb folder. You can’t delete individual items inside the dated folders.
This suggests it's not wise to delete the Photos folders using Finder either, as they're inside a dated folder. And Terminal is out too:
Don’t use Terminal or any other app other than the Finder to move, copy, or remove items from the Backups.backupdb folder.
Is there any safe way to delete the unwanted volume snapshots while preserving the integrity of my Time Machine volume?