You don't need that add-on anymore. It's now very easy to connect your Google Calendar to Thunderbird. All you need to do is go to the File menu > New > Calendar > On the network. Enter your Gmail address in the User name field and click Find Calendars. A webpage will open for you to sign in to your Google account and grant Tbird access. From there it should be smooth sailing. One less incompatible add-on to worry about.

Regarding automatic updates, I'm not aware of Thunderbird forcing updates irrespective of your settings. I have Tbird 78 set to not auto update and while it's offering v91, it's not installing it automatically. You probably have a third-party software updater that forced TB 91 on you. They don't respect your preference to not auto-update.

You don't need that add-on anymore. It's now very easy to connect your Google Calendar to Thunderbird. All you need to do is go to the File menu > New > Calendar > On the network. Enter your Gmail address in the User name field and click Find Calendars. A webpage will open for you to sign in to your Google account and grant Tbird access. From there it should be smooth sailing. One less incompatible add-on to worry about. Regarding automatic updates, I'm not aware of Thunderbird forcing updates irrespective of your settings. I have Tbird 78 set to not auto update and while it's offering v91, it's not installing it automatically. You probably have a third-party software updater that forced TB 91 on you. They don't respect your preference to not auto-update.

Many thanks for the answer. It actually seems to be working again now but I'll try uninstalling the add-on and using the direct method when I have more time.

No idea what caused the auto-unpdate but it was the setting in TB that had changed. I had set it to prompt but when I checked today (as I was surprised to get an update message) the setting was on auto.

Thanks so much

The built-in solution does not appear to support shared private calendars, so yes, I still need Provider...

The built-in solution does not appear to support shared private calendars, so yes, I still need Provider...

Neither tasks are supported with the built-in solution. At least, I didn't find how.

mikael791 povedal(a)

The built-in solution does not appear to support shared private calendars, so yes, I still need Provider...

Neither tasks are supported with the built-in solution. At least, I didn't find how.

I am not sure whether this is the same problem as I had. I have added other people's calendars to my Google calendar and wanted to see them.

I found that if I go to the calendar settings (hover over the calendar and click on the 3 dots to the right of the name, then choose the settings option), close to the bottom of the page there is a section called 'Integrate Calendar' which has a 'Calendar ID' field/item. I found this field either contained a username like 'somerandomletters@group.calendar.google.com' or 'name@gmail.com' If you put that into the 'Username' field and click 'Find Calendars' then it will work. It may pre-fill the other person's username, but just replace it with your own and log in using your account as you did for your own calendar.

The solution by @christian_chess_geek indeed works, for shared calendars! Thank you so much.

By the way: thunderbird thinks it is getting read AND write access to those shared calendars, even if the settings at Google say it's only read access. Don't let Thunderbird confuse you. If you try to make an entry for a shared calendar, it will not be written (as it should be, in case of read-only shared calendars)

p.s. it would be nice though, if Thunderbird could recognize these shared calendars when connecting by itself. This way, I have to manually add 10+ calendars of my coworkers, one by one. And I'm afraid, after the next Thunderbird update I will need to reenter my credentials 10+ times again, with 2-factor authentication...