Re: How can I remove a no longer used time machine backup?

If you "Enter Time Machine" from the menu bar, there is an option in the gear menu to delete the entire backup. I don't know that this works any different than the other options, but at least it is an explicit option for the required task.

Me personally, I would only ever use disk images or sparsebundles on a volume I intended to share with other files. Then you're just trashing one file (or maybe several thousand with a sparsebundle - but still less than easily millions in a Time Machine backup). Otherwise a volume dedicated to Time Machine allows reformatting, and then you get an all new set of b-trees. I just don't trust how messy the file system gets with creating that many files, and then just deleting them. I'd start over.

Chris Murphy