hello, does it make a difference when you disable hardware acceleration in preferences > advanced > general? otherwise please also go through the troubleshooting steps covered in Websites look wrong or appear differently than they should...

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode

You can do a font test to see if you can identify corrupted font(s).

• http://browserspy.dk/fonts-flash.php?detail=1

You can try different default fonts and temporarily disable website fonts to test the selected default font.

• Tools > Options > Content : Fonts & Colors > Advanced
• [ ] "Allow pages to choose their own fonts, instead of my selections above"

Dear Madperson, Thank you for your directions, but they didn't work for me!neighter disabling hardware acceleration nor steps covered in your troubleshooting link.

Dear cor-el, thank you for your really helpful notes. And the Font solution worked! but how can I find out what fonts have problem on my system in order to fix them?I want to see pages with their original fonts as before! (my loving google appears different)

Did you manage to identify which font isn't working properly?

You may have to remove that font to make Firefox use a different font. --- (I see that you are on Linux. I hadn't check the system details before, so sorry about the Windows menu path)