Google requires completing authentication in Safari

"Anyone in their right mind would definitely not grant macOS that permission."

How else are you supposed to use any mail client, like Apple Mail?

An e-mail client will need to connect with your account using IMAP and that, by definition, means that what you have on your mac mimics the contents of your account on the server. If you do NOT allow deleting messages, moving messages, etc, then at most Mail would work as a viewer, but you could not use it as you normally would. If that is how you feel, use only Gmail's webmail interface.

I download my messages, file them in mailboxes and, yes, delete a lot of them (either because they are useless spam, or simply because they've achieved their purpose and I don't need to keep them). And I do that using my preferred e-mail client, Mail. Who doesn't do that?

I downloaded macOS X 10.14.5 yesterday. Since then Mail is telling me that "Google requires completing authentication in Safari." about once an hour!

It is driving me crazy. Why can't it recognize my Mac when I have ticked the box asking it to remember?

Is it a new bug in Mail?

So does anyone know if Apple is going to come up with a fix for this? There is no way to use Apple mail with this Mojave update. Thanks,

This seems like a trap to delete everything off gmail. Is this part of an Apple vs Google battle?

Yes.

Not sure if that is what happens to you, but that authentication sheet had an ok or confirm button that came outside the visible area and require scrolling to be seen and clicked on.

Yes, I saw it and ticked the box that said not to ask again. Obviouslythat was ignored...