Please tell me you have been doing backups of your profiles.

131.0 is for current purposes a beta that should neither be upgraded to nor installed in a production environment.

What version were you running prior to Oct 1?

Since I was on auto-update I wasn't paying much attention to current releases, but believe it was 128.2.3.

Wish I could tell you I was doing backups. Prior to retirement March 1st, my company's MSP was backing up my personal system, but I'll need to check with them. Can't count on a backup.

Noted just now that my Thunderbird installation reverted to 131.0 (again). It may be that the profile in use contained the auto-update feature which fetched Mozilla's latest, as before.

Confirmed this is what happened -- auto update was set and T-Bird updated & installed 131.0. Can't understand why Mozilla would auto-update with a beta release. It's suggesting I downgrade (again), but I won't until I find a path to resolve the profile issue.

Where did you install Thunderbird from? You are likely on the release channel and likely wanted to be on the esr channel. This is likely a problem with a 3rd party packager using the wrong channel, or you updated the channel manually.

See Update Channel at Help->Troubleshooting Information.

I don't recall noticing a specified channel while on auto-update. In reverting to 128.3 I first clicked the link in 131.0 beta warning which I assume took me directly to Mozilla. In subsequent reinstalls I went directly from the Mozilla download site and the new profiles created all end in .default-esr. Thanks for the note and link to troubleshooting. I'll check it out.

Thanks to input from Corey & Wayne, I found my previous profile, re-implemented TB and can now access my full calendar & email history and structure. Relieved. Albeit on 131.0 after the last 2 unexpected auto-updates.

Corey was correct -- I have been on the release channel, not esr. Don't know how I got there. In another post earlier today, David mentions that the "release" channel hasn't been released yet, but on a TB implementation 2 years ago (different machine running 91.11.0) application basics->update channel = "release" Curious.

My quandary now is whether to start this process over, attempt another downgrade to 128 and risk profile incompatibility again.

Is there no other way to change release channels from update to esr than to uninstall/download/reinstall Thunderbird?

> Is there no other way to change release channels from update to esr than to uninstall/download/reinstall Thunderbird?

No.

If this is a production environment, then you should not yet be using release channel and instead use 128. See https://support.mozilla.org/en-US/kb/unable-launch-older-version-profile for advice.

Thanks, Wayne. First, no not a production environment or a developer. I'm just a long time (~18 year) retail user. I never intended to be on the release channel and don't know how I got there. All my updates, to my knowledge, have been direct from thunderbird.net and not a 3rd party.

Second, I read that article and believe that it's either incorrect or, at least, misleading. It is definitely dated. The article's contention that you can get to a previous profile used in a newer release from a downgraded TB via Profile Manager does not appear to be the case.

After downgrading & reinstalling 128, my last profile (the one used in 131) was shown in Profile Manager. However when attempting to launch or use it I'm offered the same message with 2 options: exit or create a new profile. Having closed Thunderbird with the previous profile designated as "default" now TB won't even launch without creating a new profile.

I just want to use my previous profile on the current production release, but having gone to 131, I see no way to get there. I've opened a new thread with a restatement of this problem and will close this one.

https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation is the article I really wanted to point you to.

On the command line use

-P --allow-downgrade

Wayne -- good info. Thanks.

In a reply posted on my subsequent question (1467762), David suggested deleting the incompatibilties.ini file to overcome the downgrade constraint.

Since then, I located Thunderbird backups including one the night before the 131 push to my machine and 2 more the prior week, so I haven't tried David's approach yet.

What's your opinion? Try deleting the incompatibilities.ini file or just proceed with a restore from backup? If the latter, is it just a matter of restoring the profile in use immediately prior or is there more to it than that?

John C