Okay, don't give up yet. Sometimes a new profile is created, keeping the prior profile. My first suggestion is to see if there are prior profiles. Try this: - click help>troubleshootinginformation - scroll down to 'profile folder' in left sidebar and click 'open folder' - you are now in the profile, back up one folder so that you are in the Profiles folder. - that may show multiple profiles. Only the one you are using is active; the others are dead weight - click to each of them. For POP account info, try the Mail folder to see if your account is there, and look in Mail\Local Folders to check for an local folders - check in each profile. If you find some account info that appears recent, post a screenshot of the message folders and we can assist in recovering them. thanks.

I got the problem figured out. Within my profile folder there was a file called prefs.js and also a lot of other similar files with a preceding number such as 43.prefs.js, which I assumed were backups. I opened the prefs.js and compared it with the most recent backup and found that the backup had all kinds of information that pointed to my missing accounts. I just renamed the prefs.js to something else, then renamed the most recent backup to prefs.js, reopened Thunderbird and everything was back to normal.