This issue is probably caused by a program installed on your computer. Check your list of installed programs and see if there are any that you don't remember installing or look illegitimate. Programs called Babylon or Search Protect by Conduit are often culprits.

You should also check your list of installed add-ons to ensure that there are no add-ons that are causing the issue either.

Also, you should try scanning your computer using an additional tool. You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller (for more info, see this alternate TDSSKiller download page)
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Personally, I find that AdwCleaner does the best job at finding and fixing this type of problem.

Hope this helps.

A moz-extension://e6856081-a532-44e4-8c4d-7c9c6332e602 link would normally be passed to an extension that has this UUID. When this extension is no longer installed or got another UUID for some reason then you get a moz-extension:// link instead.

You can find the UUIDs of all installed extensions on the about:debugging page. You can open "about:" pages via the location/address bar

• "about:" is a protocol to access special pages

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems