Is this a Thunderbird or Gmail generated pop up? Please provide a screenshot.

Does this help?

That's a Google error message. Google is asking you to allow Thunderbird access to your Gmail account.

So how do I fix it? Can Google "hold it over" Thunderbird? I still don't want to give anyone my permission to mess with my emails - read, compose, delete etc.

In order to set up a Third Party to access a Gmail Account, you have to alter settings in your Gmail account. Thunderbird will need permission to access and delete emails in the Gmail account - that's the nature of a Third Party Email Client.

SO, if I understand you correctly, to continue using Thunderbird I have to sign away all my privacy rights and allow someone else the opportunity to read all my emails and the be able to delete whatever they feel like (without checking with me whether or not I want to keep it) and also to be able to use my email address to compose and send emails with my name on them to anyone they feel like? That opens up MY name to accusations of spam, scams, and lots of other stuff.

And if I don't agree and don't sign, I can't use Thunderbird any more?

Its no wonder that we have so many problems.

Is there no way around it? Yet I can continue using Gmail in my browser with no problems.

SO, if I understand you correctly, to continue using Thunderbird I have to sign away all my privacy rights

No that is not even vaguely correct.

and allow someone else the opportunity to read all my emails and the be able to delete whatever they feel like (without checking with me whether or not I want to keep it) and also to be able to use my email address to compose and send emails with my name on them to anyone they feel like? That opens up MY name to accusations of spam, scams, and lots of other stuff.

That someone is YOU! Not some nebulous "other". You want to manage your mail in Thunderbird, I assume that is why you installed it. When you decide to delete an email you want it deleted. Without giving the TOOL (Thunderbird) you have chosen to use the ability to delete it can not. The same goes for all of the other "permissions" which you think are some sort of loss of privacy or control or something.

And if I don't agree and don't sign, I can't use Thunderbird any more?

That is essentially correct as you have chosen not to allow Thunderbird access to your email. Thunderbird can not authenticate with gmail to get your mail and do its job, there would be no point. It is not you can not use Thunderbird. You have chosen not to.

Its no wonder that we have so many problems.

I simply do not understand that statement at all. The choice is yours. All that is changing is your authentication method. Thunderbird could as your agent always send mail etc. using your user name and password. Now you are being told that the actions you undertake in Thunderbird will affect your gmail data and being asked to explicitly allow what has been going on for 20 years.

Is there no way around it?

Of course not. Google /Alphabet have decided oauth is the authentication method they will allow for the accessing of gmail accounts, contacts and calendars. Personally I see absolutely no reason to even try and get around it as it is actually more secure than two factor authentication. </blockquote> Yet I can continue using Gmail in my browser with no problems. </blockquote> Not in any way related.

Matt, thankyou for such a clear answer.

I've been using Thunderbird for over 25 years and never had any problems so when this popped up I wondered what's going on, and whether I had caused a problem. There was no go explanation with it.

So if I just click the yes (or agree) button I should be back to "normal" (at least, as it was for me). I've been trying to make do with the gmail on browser but there are limitations that try to do mu head in and I'm keen to get back to the Thunderbird that I know.

Thanks again

- Ashley