Please update to the latest version which is 22.0. http://getfirefox.com

Please update to the current Firefox 22.0 release.

• Help > About Firefox

• https://support.mozilla.org/kb/update-firefox-latest-version.
• https://support.mozilla.org/kb/Updating+Firefox

The Firefox 12 version that you currently run is no longer supported with security updates.

• It is important to update Firefox and add-ons to the latest version to get all security fixes.

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.sqlite, extensions.ini) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

• https://support.mozilla.org/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
• https://support.mozilla.org/kb/Unable+to+install+add-ons

If you see disabled or not compatible extensions in "Firefox/Tools > Add-ons > Extensions" then click the Tools button at the left end side of the Search Bar ("Find Updates" button in older Firefox versions) to check if there is a compatibility update available.

If this hasn't helped then also delete the addons.sqlite file.

I updated Firefox(although why it didn't update automatically like it is supposed to, I have no idea), and my add-ons still won't work. I tried to delete them and re-install them, they still won't work. I discovered under the "view", and "Tool bars" tabs, a tool bar called add-on bar, but when I check it, I don't see any new bars.

Did you try to delete some files in the Firefox profile folder like I wrote above?

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

You can also check for problems caused by a corrupted localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf

By the way, what add-ons aren't working?

Not all add-ons create entries on the Tools menu or icons on the Add-on bar (which usually appears along the bottom of the browser window). You can check for an Options button here:

orange Firefox button (or Tools menu) > Add-ons > Extensions category

Auto close tabs and clean up tabs.

I am new to add ons.

About 6 months ago I installed addblocks and no problem. A bit later I was trying to install some others and the same problem happened to me. They show in the add ons tab, but not in the add ons toolbar. I tried all the suggestions mentioned above and nothing so gave it up.

Today I tried a couple of Youtube downloaders add ons recommended by Firefox and still the same problem. Also they should show up on the you tube window to work but nothing.

My 'xpinstall.enabled' doesn't have any TRUE or FALSE value. But I have installed software so...

I have tried to work this out without success. I don't know what to do anymore.

Thanks to all. diego

Hi diego72, did you check whether the add-on buttons are in the Customize dialog? You can access the dialog and drag buttons between toolbars using the methods described in this article: Customize Firefox controls, buttons and toolbars.

If that doesn't help, could you start a new question and include a list of your add-ons with your post: https://support.mozilla.org/questions/new/desktop/fix-problems