hello, this sounds like the files in your profile folder that store the information about your extensions might have become corrupted. please go to firefox > help > troubleshooting information > profile - show folder... then windows explorer should open up your profile folder. in there look for the files named extensions.ini, extensions.sqlite, extensions.sqlite-journal (and in some cases also extensions.txt, extensions.rdf). delete or rename those files and quit firefox, they will be regenerated the next time you launch firefox.

also see Corrupt extension files

You may have to delete compatibility.ini as well to force Firefox to rebuild the caches.

only had compatibility.ini and extensions.ini and deleted them however it didnt help. how do i force ff to rebuild the caches?7

Try to delete a possible user.js file and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in the current Firefox release.

If it doesn't help then create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

i tried creating a new profile which didnt help either

If you have software like Advanced SystemCare that might reset some files to older versions to protect these files against changes then check the settings or uninstall this software.

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if this helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

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