How to delete mail saved in profiles from imap accounts no longer in use.

Question

I have been trying to transfer old e-mail from a closed G-mail account to a new one. The messages from the closed account are downloaded on my computer (MacBook Pro w/ Mavericks 10.9.4). I need to move them to an on-line account; i.e., a new G-mail account. This has been a trial and error process, during which I have had to use a couple of different G-mail accounts, because the methods I used to copy messages failed. I've now found a method that works, using the Thunderbird "copy to" function (the "copy folder" add-on never worked for me). So I am transferring the messages 500 to 1000 at a time. The problem is that during my prior attempts to copy or transfer, Thunderbird downloaded the messages. So now I have multiple partial copies of the original e-mails saved on the computer. My Thunderbird profile shows saved mail from 4 e-mail accounts. I want to get rid of 3 of these, including the original downloaded account, leaving only the download associated with the G-mail account to which I am successfully copying the messages. How do I do this? Can I edit the profile to delete the imap.googlemail-x.com and the associated msf file? I have already de-linked two of the temporary accounts from Thunderbird, but the downloaded mail is still there. Thanks for any insights.

Answer 1

Please don't open duplicate threads for the same problem. Follow-up at your other thread.
https://support.mozilla.org/en-US/questions/1018746