..... won't download ??? Or cannot install? Where do your try to get the Thunderbird Mac version from? Try once again going to this page https://www.thunderbird.net/en-US/desktop/

Thanks for the quick response.

When I click on the download button, I'm taken to the donation screen. I've made a donation if I do get past the donation screen and click on the download button the donation screen pops up again.

I just tested to download the "Thunderbird.147.0.1.dmg" installer disk image with Firefox from the linked page. The download was very quick and at its end a popup window indicated that the download was terminated. At the same moment the https://www.thunderbird.net/en-US/desktop/ web page switched to the donation screen and the Thunderbird.147.0.1.dmg icon appeared on my Desktop. Maybe at the end of the download you didn't notice that in the meantime the download action had taken place....?

My desktop is the "target folder" when I download files or folders using Firefox. I don't know to which directory you download files, but did you verify whether it contains the Thunderbird.147.0.1.dmg installer disk image?

I feel a bit of an idiot for not checking if it had actually downloaded, which it had.

Thanks for you help.