If you are creating a Gmail account, Google will pop up to verify your account. when you enter password and click the 'ALLOW' button, Google then places a secure password in your Thunderbird account and does not pop up again. This is a required step done by Google, not by Thunderbird. I hope this information helps you..

but i dont try to creat a gmail Account. I got my own Mail-provider and dont use Gmail in any kind.

Then I am puzzled on why Google interferes. Maybe someone else here has suggestions.

Hello, I need help to get rid of the Google window. I don't want to log in via Google if I can do it via Mozilla. The Mozilla credentials do not work. Please tell me how I can solve the problem. I can't click on the links in the window because the window turns white. I can only click it away, but it comes back within 5 minutes. Or I can log in with google, which I don't want to do. Thank you for your help. Eva Langenberger

If you don't have a gmail email account in TB, did you ever add a Google calendar or Google Contacts, with or without an add-on?

My employee uses the calendar, and she also receives the message. However, she doesn't have any Google account, calendar, etc.

I don't use the calendar. Someone said it might be related to the "Datenschutzerklärung" (privacy policy), but when I click the link, I only get a blank window. It's really annoying.

Even when I start in the error-finding "Fehlerbehebungsmodus" (troubleshooting mode), the message still pops up.

Oh my God, I solved the problem. It was the calendars. A calendar add-on for current holidays was linked with Google. I deleted it and the annoying message disappeared. Without your help and the resulting insights, I would never have found it. Thank you all."