Hello there Chuck

Right-click your calendar, select "Properties," and uncheck "Read Only" to ensure proper syncing.

What calendar do you use?

Stop automatic responses To stop automatic responses, go to the Config Editor. Navigate to Settings > General > Config Editor. In the search bar, type calendar.google.enableEmailInvitations. Double-click to set this value to 'false', then restart Thunderbird

Hello there Chuck

Using filters Disable the auto-response filter by opening message filters and marking the box as turned off

Hello there Chuck

This persistent issue in thunderbird , where do not send a response is ignored

Change calendar properties Go to the Calendar tab, right-click your calendar on the left, and select Properties. Check there to see if there are settings that force replies. Also, make sure that your email address is correctly linked to the calendar.

If the issue persists , the issue might be a corrupted configuration.try creating a new thunderbird profile via the profile manager to see if this issue is resolved,as suggested

Turning off lightning In case that you use lightning try to turn off that add on. Re-enable back that add on to see for behaviour.

You might have a bug If it s still sends notifications to surrounders.

Right-click your calendar, select "Properties," and uncheck "Read Only" to ensure proper syncing.

Good morning.

That was the very 1st box I made sure was unchecked when I originally added my GMail account / calendar last month.

What calendar do you use?

I use GMail as my main calendar.

Stop automatic responses To stop automatic responses, go to the Config Editor. Navigate to Settings > General > Config Editor. In the search bar, type calendar.google.enableEmailInvitations. Double-click to set this value to 'false', then restart Thunderbird

I just completed this. When I copied and pasted what to type, I got a + sign. I didn't change the default (I think it was boolean) and when I clicked the + it was true. I double clicked and changed to false. I will see what happens next time I get an invite.

I appreciate it because that is such a PITA - 98% of the time I say don't send a response, and they always get one.

Hello there Chuck.

I did read that message, Chuck. We can go through a few subjects

Can you relink ? Remove the google calendar in thunderbird, And add it again via  : calendar> new>on the network.

Can you send us smtp settings Please send us your Smtp settings?

Troubleshoot mode Start up in this mode to check if an extension is the culprit here. https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Clear cache You can actually clear the cache by going to Calendar Properties in Thunderbird. Right-click your calendar, select Properties, and choose the option to refresh the cache. Alternatively, turn it off and on temporarily.

Use https://support.mozilla.org/en-US/kb/how-to-make- screenshots

https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

Has it been useful to be able to use any of these subjects?

Hello there Chuck

Overriding thunderbird Google often overrides rules set in Thunderbird. Also, a server-side issue is already there causing it

That is why I recommend deleting the Google Calendar and reinstalling it. Did it changed something?

Hello there Chuck

To give you that second view Deleting that Google Calendar is a good idea; it might be outdated. OAuth 2.0 data from 2025/2026 is considered outdated, as the new standard is OAuth 2.1. Here is a tip: Remove your current Google Calendar in Thunderbird. Go to File > New > Calendar > On the Network. Enter your email, leave the location blank, and follow the prompts to authenticate. Re-adding it this way will give you the most recent stable connection. If you leave the location form empty, Thunderbird will handle it automatically.