Rated 5 out of 5 stars

by Up2you2 on Nov. 8, 2021 ·

Finally a solution that works, mine is ciurrently set at 1.45, this works best for me.

https://www.askwoody.com/forums/topic/cant-change-email-font-size-thunderbird-for-macs-stuck-in-tiny-letters/

Looking around in the Web, it turned out that there are lots of complaints about the tiny fonts.

I found a solution, it is not exactly perfect but certainly gets around the tiny font size problem:

https://support.mozilla.org/en-US/questions/1297871

It means using “About Config” by clicking on “Config Editor” at the very bottom of the page in: Thunderbird/Preferences/General, then accepting the “risk” (I understand there is no such risk, just a sort of in joke), then searching for “pixel” in the search field there, and clicking twice on this line: layout.css.devPixelsPerPx .

In the window that opens change the default “-1” to something bigger, but not too big, then click OK. In my case “3” works. Make sure that the “-” has been removed when changing the value from -1 to some multiple 0f 0.5, while keeping in mind that larger than 3, going by my own experience, might be too large and inconvenient, as changing from -1 on up increases all the font sizes everywhere in Thunderbird (and only in “Thunderbird”), including the “Inbox”, so everything there gets crowded and some goes out of sight if one chooses a number that is too big. The moment you click OK, you’ll see the effect of the change in the very “Config Editor” page you are in.