Help/Troubleshooting, Profile Folder, Open Folder, to view the profile folder. Messages are stored in account subfolders, e.g. pop.gmail.com, of Mail (POP accounts) and ImapMail, and Mail/Local Folders. Which of the mbox files, the large ones with no extension, named after folders, are taking up most of the space? Is All Mail a subscribed folder in TB?

All Mail nstmp-1

I have 4 gmail accounts feeding into Thunderbird. I assume each email account will have it's own profile? The All Mail and nstmp-1 are from just one profile. Also when I look at the files via the path you suggested the files I see aren't very big. When I look at them via my Disk Savvy tool they are huge.

If all the accounts appear in the left Folder Pane, they are in a single profile. Each account will then have a separate subfolder of Mail or ImapMail. Most users unsubscribe All Mail and then delete the All Mail mbox and All Mail.msf. See the All Mail section here.

http://kb.mozillazine.org/Nstmp_folders

I think that fixed it. Thank you!