My understanding is you have two accounts: one is imap and one is pop and you want to remove the pop account. Go to tools>account settings then highlight the account to be removed and farther down the left pane you will see 'Account Actions' - click that and one option is 'remove account'.

Also, your imap account is also subject to Google's warning about OAUTH2. Using OAUTH2 has been an option for several years and now it will soon be mandatory for Gmail. TB has that option and it's rather straightforward. You need to change authorization by going to tools>account settings>server settings and changing authentication method to OAUTH2 and then going to tools>preferences>privacy&security and remove the gmail passwords - highlight account, rightclick and remove password. After that, shut down TB and restart. You will be presented with a menu to log into gmail to grant access to TB. Once done, life should resume.

David, thank you for your advice. Unfortunately I am now thoroughly B***ered. I followed your clear instructions about removing the pop3 account. I then started on your imap instructions. I appears that the imap account is already using AOUTH2. So I did not do anything about the gmail passwords. There were 2 of them, one the one I use on my google acoount, the other (a very long string of random characters) was associated with the imap account. As instructed I closed TB and restarted. My pop3 account had disappeared, unfortunately so too had all my associated folders. I have now no access to any of the very important stored emails. I have a backup of my TB profile, but is there anyway I can get to the lost folders without going the horrendous route of digging out the backed up TB account and info?

My regrets on the confusion. To me, an account includes all message folders. I suggest you look in the profile folder in the Mail folder. I think the messages will still be there. You could then create local folders, shut down TB, and then move the message files to replace the dummy files that were created.

May well be feasible, if you're an expert. I'm not, and have no idea how to set about doing what you suggest. I can follow instructions but not wing it. What makes it worse is that TB is now not showing any account and asking me to set up a new one.

You lost your IMAP account? All I can guess is you also highlighted that account when you removed the POP account. From an earlier post, I inferred that the POP account was all that was lost. At least the IMAP account can be recreated with no data loss.

On the POP data, you will need to look in File Explorer, going to c:\l(yourID)\appdata\roaming\thunderbird\xxxxxx.default (that name will vary, but ends in default). and then look at Mail folder and, from there, Local Folders. You may see folders ending in .SBD or files ending in .MSF. Those are the files to recover. Please post a screenshot of what you see in Local Folders. I'm anticipating a list of files and/or folders. Thanks for your patience.

IMAP account disappeared later, must have don't something unexpected when trying to restore TB files from backup. Have set up new IMAP account. Drilled down to TB profiles. 2 showed, one ending default only held 1 file - times.json. The other ending default-release had lots of folders/files. Attached is screenshot of local files from this profile. Hope that's all ok

Those files look empty. You might look in the Mail folder itself for similar files.

You might also browse the c:\(yourID)\appdata\local\thunderbird folders to see if any such folders are there. This area is generally for cache, but it's worth investigating.

In the Mail folder there were 2 sub folders, local (which you said looked like empty files, and another titled mail.****.org.uk. This contains folder Inbox.sbd - size 426Mb and other files - see attached. They all seem to be paired, ype 'file' and 'msf file' Could this be what I want, and how do get them incorporated into the IMAP account?

You may be better off keeping it in Local Folders, as I don't know what IMAP account would do if it sync'd with online content. To access the files, you must first 'fool' TB by creating dummy folders of the same name. My suggestion: - close TB - in File Explorer, move the files/folders to another folder - now, start TB, highlight local folders, right click and create a dummy folder for each of what you showed me (but leave the .sbd off), e.g., Inbox, Sent, Trash, etc. Spelling must be exact. - now, exit TB and move the previously copied files/folder there. You will be prompted to overwrite existing files. - Now, start TB and if all went well, you should see messages.