Please update to version 78.2.2 which just came out a few minutes ago. Any improvement?

The version installed is 78.2.2 and the issue still remains. I cannot create a task nor an appointment in my Google calendar from within Thunderbird. At that point the app stops and the wheel of death pops up. Keeps spinning no way to terminate the app only by CTRL ALT DEL and stopping app or switching on and off the laptop. Where after the task/appointment does appear in THunderbird.

Thanks for support.

If you are using provider, then you want to report the issue at https://github.com/kewisch/gdata-provider/issues

I reported to the developer. Let's wait his reply.

I have this problem if I try to do an update on a calendar I'm not authorised to update, eg my wife's google calendar which is linked in as read only.

This information was useful and not. I checked the permissions on the Google Calendar and indeed there was no sharing created for the email account running on the Thunderbird. So I selected SHARE, entered the email address. Google replied that the address is non Google so an invitation must be send and accepted. Done. In TB I accepted the invitation but the address still does not appear in the Google Calendar settings. After quiet a lot of discussions with my provider of the TB email address it turned out they did not support Exchange features and those are needed for the Provider app in TB. Conclusion: It is not possible to update a calendar from TB towards Google. One can read but not amend.

I would like to know now how I can create a calendar and tasks in TB and maybe share this with Google. The other way around, would that work?

I definitely have a two way update with Google Calendar for my own calendar, with the Google Provider. Works perfectly. Under properties of the calendar you should have this googleapi://xxxxxxxxxx@xxxxx.co.uk/?calendar=xxxxxxxxxxxxxxxr%40gmail.com and provided you sign-in it works.