Hi Steve, have you been running Firefox Beta for a while and this just started? There appears to be a radical difference in aliasing between the two screenshots.

Can you check whether any of Firefox's font rendering settings have been modified:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste font_r and pause while the list is filtered

If anything has been customized, you can reset it to its default value by right-clicking the preference and choosing Reset.

You can see the problem. FF installed this version automatically. All of the entries found by font_r had reset greyed out.

If I am running a beta version, I will download a RTM version and see what happens.

I don't want to lose my history or bookmarks, although history I can lose.

Something has got screwed up.

It's possible that there is a block on your graphics card/chipset driver software; that could severely degrade the anti-aliasing. That might be indicated on the Troubleshooting Information page, Graphics section. Either:

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

I think the Direct2D row might be the most relevant.

See also: Upgrade your graphics drivers to use hardware acceleration and WebGL

I have the latest driver for my graphics card, however it is an old card not supported on Win 10. I have re-installed the driver lately due to other issues.

It has been running fine up until lately, not sure if it is win 10 update causing the problem.

The following error shows in the troubleshooting.

WebGL 2 Driver Renderer WebGL creation failed:

• Error during ANGLE OpenGL init.
• Error during ANGLE OpenGL init.
• Error during ANGLE OpenGL init.
• Error during ANGLE OpenGL init.
• Error during ANGLE OpenGL init.
• Exhausted GL driver caps.

Also,

WEBRENDER opt-in by default: WebRender is an opt-in feature unavailable by runtime: Build doesn't include WebRender

Hi, I have solved the problem. For some reason clear type text had been deselected.