Try pressing F11 to get to full screen prior to setting the account.

Thx much for your suggestion. Alas, pressing F11 does not get my TB to full screen: all it does is add a calender/events to the right of my messages of my old/existing email account (on the still reduced-size Thunderbird screen).

When I click on the square in the top-right corner of TB, it goes to full screen on my (less than two-year old) Dell laptop. When trying to add a (gmail) email account to my laptop TB that I've been using on my desktop for many years, I get stuck in the final step, a full screen labeled Google account.

It shows the new email address I'm trying to install, and then the words This will allow Mozilla Thunderbird Email to: - Read, compose send ... (etc.) - See, edit, download ... (etc.) - See, edit, permanently delete ... (etc.) followed by a line saying: By clicking Allow, you allow this app and Google to use this information.

That's all I can see on that screen: I don't see an 'Allow' button that I can click, I can't move the image or change its resolution in order to get an Allow button to appear. I'm stuck ... basically unable to use that (for me precious email account) on my laptop.

Any other suggestions would be appreciated.

Puzzling. Does the window pop up in thunderbird or the browser? Try pressing f11 when the popup shows.

Indeed puzzling. Pressing f11 when the popup shows does nothing. And whether the window pops up in thunderbird or the browser is something I can't say for sure: it could be either one. To get out of that full-screen pop-up, I press ESC and that gets me back to thunderbird.