What have you done?

Provider for google calendar is a helper to allow the google calendar to synchronize with Thunderbird. It is not needed unless you are using Google tasks and want to synchronize those.

So I am guessing you have two calendars in Thunderbird now when you are in the calendar tab. One with your data in it and an empty Google one. Can you confirm that?

When you try and export from Thunderbird you need to select the calendar that has the data. That is not the google one is about all I can tell you as I do not know what you chose to name the calendar when you created it.

When you export, I am assuming you use the events and tasks menu and choose a calendar from the list offered. Make sure it is the correct one that contains data, not the one you want it in.

Hi Matt! Thanks for your answer. Unfortunately that exactly doesn't work. Yes, I have these 2 calendars. Exporting the new for google one, with only one new appointment in it, is not a problem. If I do the same with the one I used until now, with some hundred appointments in it, it just don't export one appointment of it. It just get an empty file. Martin