Everything was working fine in Thunderbird until the recent update to 60.0. Now when I open a message the fonts are sometimes very ugly – thin and washed out with occasional bold-looking appearance (for example the combinations “ti” and “tt” look almost bold face). It’s difficult to pin down exactly when the fonts are ugly, but sometimes messages look fine, sometimes the entire message is ugly, and sometimes only quoted previous messages are ugly. I’ve tried the following:
More→View Source: look for strange or specific encodings. Nothing unusual here, sometimes Content-Type: text/plain; charset=“utf-8” displays fine, sometimes it doesn’t. Couldn’t really find a correlation with charset.
Preferences→Display→ Fonts and Colors → Advanced: Check that legitimate fonts are chosen for the various options (serif, sans serif and monospace); tried switching to other fonts and that didn’t make a difference. Problem happens whether “Allow messages to use other fonts” is checked or not; some OK text reverts to the bad font when it is unchecked though.
On googling, I found this issue http://z-issue.com/wp/ugly-fonts-in-mozilla-firefox-and-thunderbird-under-linux-skia-and-cairo/ and had high hopes, but when I checked, my config file was already set to cairo.
Any suggestions out there?