I think something is wrong with calendars in general today because I just started having a problem that may or may not be related.

One of my shared calendars disappeared while I watched this morning. Everything was in the sidebar then the shared items disappeared one by one. I tried removing and re-adding the calendar but no luck. Now it has an exclamation point in a triangle and says "The calendar [person's name] is momentarily not available"

Also on 102.3.1 but I'm not sure when it updated.

My computer notified me of the Thunderbird update yesterday afternoon (3 Oct 2022) and Thunderbird updated on startup this morning. I found a number of articles about Google Calendar problems starting back in July and I think I've had a couple of updates since then, but this is the first time one of the calendars has gone 'missing'. (I also tried an export to ics and the current month's events seemed to be there... just couldn't see them in Thunderbird.)

As an update, I closed Thunderbird and I tried renaming the calendar from ToDo to Schedule in Chrome>Calendar, but it made no difference. In Thunderbird, it's the only calendar that disappears from all months after changing to another month... such a pain to have to unsubscribe and re-subscribe just to see events for the month currently shown.

Thanks for the reply - hopefully they'll get it fixed quickly.

I am having the same issues this month. I have 23 different calendars. February 2020 they all show up, March 2020, only 3 show up. This "changed occurred within the last month. What is going on? How do i get my calendars to show up again on the current month?

Well, I've now updated to Thunderbird 102.3.3 (64bit) and (after 'workaround' below) still, the same calendar disappears after changing to a different month. The only 'workaround' I've found is to unsubscribe that calendar in Calendar, go to gmail account and re-subscribe to that calendar... and it's back until I change to different month. Sorry, but the workaround is NOT a solution.

Just an update: updated to 102.4.0 and the calendar still has to be re-subscribed to see each month.

just how are you subscribing? that is the question.

Way back when I was trying to understand some of the integration changes I was pointed to https://calendar.google.com/calendar/u/0/syncselect?pli=1

This link actually enables subscription for calendars on Google. I was mystified why not all my calendars worked until I had that pointed out.

Then there is the provider addon, this was required some 10 years ago. Not so much now. But it does offer a task list that the native caldav does not. Too quote the FAQ "The Provider for Google Calendar also allows access to Google's task lists " I have no idea about a todo calendar.

My feeling is you are all using the provider addon and need to contact the author for support with it. But that is only a guess base on a similar sound to the issues shown here https://github.com/kewisch/gdata-provider/discussions

Thanks for the reply Matt. Unfortunately, the first suggestion seems to refer to "Select calendars to sync to your iPhone/iPad/iCal*" whereas I'm having the issue with Thunderbird on a Windows 10 PC (update current). Everything looks OK as the Google Calendars that show as well as the one that doesn't are all check-marked. I also looked at the 'provider addon' and see there are lot of unanswered questions that (barely) seem related, but no issues are for "one calendar of many is 'missing' unless a resubscribe is done"... and then the one calendar only works until a change to another month when it disappears again. Yes, I'm using addons: Lightning Calendar Tabs (last Update 17 Aug 2022) Open Google Calendar (last update 13 Dec 2020) Provider for Google Calendar (last update 22 May 2022) Remove Duplicate Messages (last update 9 Aug 2021) Nothing seems to answer why one calendar doesn't show, while multiple other calendars work fine. Calendars that work: Personal (local) Contacts (from Google) Holidays in US (from Google)

• • • • @gmail.com (from Google)

Medical (from Google) My List (from Google) And the only calendar that has to be resubscribed to be seen for only the current month: Schedule (from Google)

PS. tried to submit a bug yesterday... still waiting for the email from bugzilla to create an account.

Google offer you a list of possible sync solutions using caldav and because your chosen application is not listed. You stop.

If you actually want to get the thing working just accept that Thunderbird should be on that list and continue. That is all.

One thing I think I can assure you. This is very unlikely to be a bug, so don't waste your time and that of someone in triage (possibly me again) filing one for you to be referred to support for your issue.

Before you do anything after verifying the list on google. Disable ALL of the addons, and I do mean all. This is a diagnostic process and addons add uncertainty as to what may be the issue.

Just to be exceedingly clear, if you subscribe to your calendar using the provider addon, then this is not the place to look for support and Bugzilla is not the appropriate place to file a bug, even if one exists. The addon authors site I linked to is the appropriate place as that is the source of the calendar sync.

Hi Matt, "Google offer you a list of possible sync solutions using caldav and because your chosen application is not listed. You stop. " So basically you seem to be saying that 'solutions' from this forum that worked for years are worthless and only Google apps/addons should be used. "If you actually want to get the thing working just accept that Thunderbird should be on that list and continue." Sound counter to your first statement: since Thunderbird isn't on Google's list, don't expect it to work. "addons add uncertainty as to what may be the issue" Apparently, addons from Mozilla/Thunderbird aren't really supported or tested and only "vendor" supplied apps/addons should be used. Bottom line: Thunderbird code changed, Google sync stopped working as it had for years and the problem MUST BE with the addons from third party vendors to get Thunderbird working with Google Calendar as Mozilla/Thunderbird claims. Solution: find another multi-email client that works as advertised. After all of the years (2 decades???) I've used Firefox and Thunderbird, I really don't want to walk away, but apparently Mozilla isn't as 'customer' supportive as it used to be. Turning off email notification. Congrats Matt!

All, Seems to have started working again. After having an issue with Google Calendar on Chrome (Monthly view only shows colored micro dots rather than colored bars for events), I found an plugin that fixed that... and an event that I'd made in Thunderbird. The event was set to repeat Monthly on the 'last day of the month', an 'option' that Calendar doesn't seem to support when creating an event. Seems the event was showing on both the last day as well as the day before (30th and 31st). After deleting all occurrences of both events, the calendar started showing in Thunderbird again. I've recreated the event in Thunderbird and it all seems to be working again.