On a system with problematic or malicious add-ons installed, Firefox may open with a blank or transparent window and with no interface elements visible. In some instances Firefox may also crash. This article describes how to resolve the problem.
Note: This is an example how an affected version of Firefox might look like.
Make sure that no other instance of Firefox is running or no other Firefox window is open.
You can then start Firefox in Safe Mode by holding down the shift key while starting Firefox.holding down the option key while starting Firefox.going to your Terminal and running: firefox -safe-mode You may need to specify the Firefox installation path (e.g. /usr/lib/firefox)
Now click on the Start in Safe Mode button in order to run Firefox with extensions and themes disabled for this session.
2. Find and remove problematic extensions
Click the menu button
and choose Add-ons. The Add-ons Manager tab will open.
In the Add-ons Manager tab, select the Extensions panel.
Look out for suspicious extensions, in particular entries that you have not installed intentionally or don't know what purpose they serve. For example toolbars that come bundled with third-party software can cause this issue. Other examples of problematic add-ons are Browser Companion Helper, Codec-C, Codecv, OneClickDownloader, TheBflix & wxDfast (this list is not exhaustive).
Click the Remove button next to such extensions or, in case it is not available, disable those entries.
Afterwards, restart Firefox.
Note: If you're unsure which extension to remove or disable, disable all extensions listed in the Add-ons Manager and restart Firefox.
3. Check your computer for malware
After completing the above steps, check your computer for malware. See How do I get rid of malware? for some recommended malware removal programs.