Is there still any mail you want to keep underneath the imap.googlemail-x.com directory?

If not, you can simply delete the account. After deleting the account in Thunderbird, the imap.googlemail-x.com directory is preserved. Close Thunderbird, and then delete the directory which was associated to the deleted account.

No, all the mail in the imap.googlemail-x.com directories has been transferred to a new IMAP account, and a separate imap-googlemail-x.com directory exists for that account.

So I can just delete the directories in the profile, having closed Thunderbird? And the msf file??

I apologize for double-posting the thread. I'm new at this, and when I looked at my questions, it looked like the first one had been truncated, so I posted again. Won't do that the next time!

So I can just delete the directories in the profile, having closed Thunderbird? And the msf file??

Yes. When deleting the entire directory you also delete the *.msf files.

Thanks for the help.