Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

• Don't make any changes on the Safe mode start window.

See:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

Delete the files extensions.* (extensions.sqlite, extensions.rdf, extensions.cache, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry. New files will be created when required.

See "Corrupt extension files": http://kb.mozillazine.org/Unable_to_install_themes_or_extensions

If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar to do a compatibility check.

Thanks neighborhood stranger! Stay tuned for update...

Nice! It works. Moz back online ... worth the switch from Chrome

Sorry for the late question, armenfly, & I'm not even sure you'll get this, but what addon was freezing your addons tab? I'm having the same problem and it's incredibly irritating.

Thanks!

Did you try my second suggestion and delete the files extensions.* in the Firefox Profile Folder ?

Help > Troubleshooting Information > Profile Directory: Open Containing Folder