Mozilla addons not working properly in ubuntu 12.04

(I assume you are using firefox, but most of these troubleshooting steps like safe-mode will work for Thunderbird as well, so they should still be useful)

Don't delete your profile folder straightaway as there's a lot more you can do before you do something like that. There are several ways of resetting your firefox data.

1) Try going to help > troubleshooting and you will see this screen (do not go to about:support without going through the menu or the reset option won't be available):

Just click the reset option and firefox will be returned to its initial state. I have just tested this and it does reset settings and uninstall addons, while retaining your bookmarks.

2) Use the special -safe-mode option to load firefox (this works with Thunderbird as well) Run from terminal,

firefox -safe-mode

You will receive a box like this, which should allow you to load firefox and see if it was an addon that was causing the abnormal behaviour. Restart firefox in safe-mode again a second time and this time click the left-hand reset button if you want to clear your settings and addons.

3) If neither of these suggestions sorts your problem out, you could run profilemanager and create a new profile and run firefox from that.

firefox -ProfileManager -no-remote

Then you could launch firefox like this or create a new shortcut, giving the exact location of your new profile:

firefox -Profile /home/mike/.mozilla/firefox/55divdmr.Mike2 -no-remote

For more on using different profiles in firefox, please see my answer here:

• How to create shortcuts to different Firefox profiles

In addition, when you create a new profile, our old profile will not be deleted, so you will still have the data and bookmarks. However, you could set the new profile as your default by placing Default=1 under your desired profile in ~/.mozilla/firefox/profiles.ini.

You could backup your bookmarks to a html file with your old profile by going to firefox > bookmarks > import & backup > export to html. You could then import these when you have launched your new profile.