Q I have put files from an old Time Machine backup into the Trash, and am now trying to empty the Trash. With over 140,000 and around 270 GB this is not making much progress. How can I expedite it?
A Time Machine backups are complex structures. Although apparently a series of complete copies of files and folders, they actually use an elaborate system of links to original copies of files and folders that can prove very slow to remove.
For that and other good reasons, it is usually best to put a Time Machine backup onto a dedicated volume. Then instead of having to move the backup to the Trash and wait for the Finder to plod through all those links and files, you can use Disk Utility to initialise that volume, which takes just a few seconds.
If you have nothing else on the volume containing those backups, and want to delete the whole of the backups, then that is by far the quickest way.
If the backup is still active, thus in use, you should avoid tampering with it, or you may render the remains unusable, with or without Time Machine. Link structures can become very complex, and it is easy to trash original content so breaking later links to that. That is also a good reason for not trying to weed an old backup by hand.
If you do need to remove old backups that are on a volume with other folders, you may find it less frustrating to drag a handful of the most recent backups to the Trash and empty it, and progressively work back in time until the whole Backups.backupdb folder has gone. This may not be any quicker in the long run, but may fit in with your other activities better.
Updated from the original, which was first published in MacUser volume 28 issue 20, 2012.