Hey, when you backup a computer that has two shared accounts on it with time machine, does it only backup the account that it is one when time machine comes on or does it back up everything on the computer?
I did a Time Machine backup for the first time today on my MBP. I also have two user accounts.
Having checked the backup afterwards, from what I could tell, it backed up everything from both user accounts. I went through the folders on the backup and could see for instance both sets of iTunes folders, the music within them etc.
Yeah it backs up everything. If you're concerned this is a waste of space, don't worry. Incremental time machine backups only save the files that have changed. So the other account wouldn't have changed when you're logged in.