Try to rename/remove xulstore.json in the Firefox profile folder with Firefox closed. You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the <b>about:profiles</b> page. *Help -> Troubleshooting Information -> Profile Folder/Directory:<br>Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder *https://support.mozilla.org/en-US/kb/Profiles You can try to disable hardware acceleration in Firefox. *Options/Preferences -> General: Performance<br>remove checkmark: [ ] "Use recommended performance settings"<br>remove checkmark: [ ] "Use hardware acceleration when available" *https://support.mozilla.org/en-US/kb/performance-settings Close and restart Firefox after modifying the setting for changes to take effect. *https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems *https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration