Simple Question: Can I rename old backup folders?

that should not be a problem except those folders are protected by ACLs that won't let you rename them from Finder. you can turn ACLs off on the backup drive, rename the folders and turn them back on. This should be done from terminal. you should be careful doing so but here are the commands if you wish.

First, turn TM off in system preferences. then run the following in terminal.

sudo fsaclctl -p /Volumes/"Time Machine drive" -d

put the name of the Time machine drive in the above. keep the quotes. you'll have to enter your admin password (which you won't see). that's normal. the command will turn off the ACLs on the TM drive.
rename the backup folders for the old computers. DO NOT touch the folder with your current backups.
turn the ACLs back on with the following command

sudo fsaclctl -p /Volumes/"Time Machine drive" -e

Turn Time Machine on.

Link Dupont wrote:
I've gone through a couple MacBooks (changed MAC addresses and such), so I have about 3 different "computers" in the Backups.backupdb folder. Two of the three folders are no longer "live" backup databases, and are effectively only around because I still want the data. I'd like to rename the folders to something more distinct when I'm "browsing other Time Machine backups". Can I simply change the name of the folder, or do I need to update some plist-files somewhere as well?

Do NOT ever modify or change anything in the TM backup directory. You will probably lose everything if you do.

1. If you want to "rename" an old backup, run TM and in the TM window which is the only proper way to access TM files, find the old backup and restore it to your computer. This is the file you can rename.

2. Now, you can rename it and let it become backed up again with the new name.
3. Finally, once you are assured it is backed up again, then using the TM interface, you can safely delete the old backup.

For these operations you use the Action gear in the TM finder window.