I've been on Thunderbird for almost 20 years and a Mozilla fan. Have evolved a fairly elaborate configuration of local (POP) email folders, rules, calendar, and accounts to manage & organize email activity, retention, archiving, etc. I've not had to deal with Profiles in previous upgrades and don't have much experience with it. The recent Oct 1 push of Firefox & Thunderbird 131.0 releases took me by surprise. I was able to re-implement the previous Firefox profile to recover bookmarks, cookies, passwords, etc. However, when T-Bird warned that 131.0 was Beta & unsupported I took the suggestion to download & install the current supported release: 128.3.0 (I was on 128.2.3). Then hell came. Once downloaded, installed & launched, Thunderbird 128.3 cautioned the new profile created with T-Bird 131.0 was incompatible with previous versions and that I should create a new one, which I did. Still could not get new T-Bird to recognize previous profile, so I tried uninstalling, downloading & reinstalling 128.3 multiple times, each time prompted to create a new profile before proceeding. I tried to follow the previous profile restoration process detailed on support forums & articles, but none seemed specifically relevant to my situation. I located my profiles in the appdata roaming profile folder, including what I think are most recent based on size of mail folders. Can't determine whether I had just one or several in use due to the extent of my setup. Could really use some help & advice to: 1) Determine which profile was in most recent use prior to T-Bird upgrade. 2) Whether more than one profile was in use. 3) Re-implement the profile I was using on T-Bird 128.2.3 with my new 128.3.0 Regards & many thanks in advance, John C Houston PS You'll ask why I would upgrade to 131.0 from 128.2.3. Answer: it was on auto-update and 131.0 is what was pushed. No more auto-updates for this guy!