Were you using the Provider add-on to sync the Google calendars? See this topic.

If you go back to 68, create a new profile with that version, in Help/Troubleshooting, about:profiles, or try to run 68 in the profile that was used by 78 by launching 68 from the command line as such:

Windowskey+R, thunderbird.exe -p --allow-downgrade

Thanks sfhowes!

Thanks sfhowes! I have my email and calendar working again.

I just got a new PC an installed this new Thunderbird. Literally nothing works! Except for adding my e-mail profiles that is... So the 'Thunderbird.exe -p --allow-downgrade' (thanks sfhowes!) wont work for me. Where can I download the old Dutch version 68.10.0? Maybe by installing that one, configuring my profiles and after that upgrade it to the new (in my opinion still bèta) version of Thunderbird the program will work as expected.

Thanks in advance,

Update: Ah found the Dutch version 68.10.0!

1. Goto www.thunderbird.net/en-US/thunderbird/all
2. Copy the download-URL and replace the version in it.

Ie. https://download.mozilla.org/?product=thunderbird-78.0.1-SSL&os=win64&lang=nl becomes https://download.mozilla.org/?product=thunderbird-68.10.0-SSL&os=win64&lang=nl.

I hope the downgrade (and upgrade later) works ;0)

- double message I cannot remove it, sorry -

Or you could just got to https://archive.mozilla.org/pub/thunderbird/releases/68.11.0/win64/ and pick your language locale.

If you have been running a profile in both 68 and 78, it's highly likely you will encounter problems, even with the downgrade option. The quickest way to get a working setup is to install TB, 68 or 78, create a new profile, either with the -p command line argument or Help/Troubleshooting, about:profiles, add your accounts and add-ons, and then transfer address books and local mail from the old profile. The previous shortcuts for reusing entire profiles in old or new versions of TB is no longer a feasible option, without excessive attention to the details.

Thanks James and Sfhowes,

I started with a clean Thunderbird which happened to be version 78 as there are no other links provided on the download/start-page www.thunderbird.net. As soon as I started to configure my e-mail, Google calendar and the Addressbooks Synchronizer (add-on). I realized the the calendar is only doable with a lot of effort like sfhowes explained here and the add-on needs a new update for TB 78.

So I simply removed Thunderbird, including the profile data from '%AppData%\Thunderbird\Profiles\' downloaded version 68 and maybe upgrade it to version 78 later. The automatic updates setting is on and it says there are no updates yet so I think I'm fine for now.

It was simply impossible to convert the profiles from TB68 to 78 since I had only TB78! Maybe in the near future when Thunderbird is forcing me to upgrade to 78 I can use the profile-solution but for now I'm fine running version 68 with no extra effort, thanks!

Or you could just got to https://archive.mozilla.org/pub/thunderbird/releases/68.11.0/win64/ and pick your language locale.

Hallo James

Thank you for the Tip. Y found my Version 68.11 in German and the downgrade had work.

Geri from Switzerland

If you have been running a profile in both 68 and 78, it's highly likely you will encounter problems, even with the downgrade option. The quickest way to get a working setup is to install TB, 68 or 78, create a new profile, either with the -p command line argument or Help/Troubleshooting, about:profiles, add your accounts and add-ons, and then transfer address books and local mail from the old profile. The previous shortcuts for reusing entire profiles in old or new versions of TB is no longer a feasible option, without excessive attention to the details.

I have the same issue.

I have email backups in my TB78 (upgraded from 68) from institutional email IDs that are no longer functional. I don't want to risk losing them. I didn't import them to Local mail (still learning what that is about).

I am a newbie. Can you refer me to a step by step solution for this? I would prefer to stay on the update channel and not downgrade.

Also, the profile structure in TB68 and 78 have changed?

Thank you for your time.