When firefox gets updated some of the extensions gets disabled. The reason for that is that Firefox extensions need to define in what version of Firefox they work. But in many cases extensions authors don’t update their extension version, or it takes some time after a new version of Firefox is introduced until a new version of the extension is out.

Firefox by default disables extensions that do not match the version, although they can still work without problems.

The first thing that you can try is to use the Nightly Tester Tools extension.

This extension adds a few extras useful to those that regularly test nightly builds of Firefox and Thunderbird.

Features:

• Allows you to force the application to believe an extension is compatible with the current version and enable it.
• Allows copying the build identifier and a list of installed extensions to the clipboard.
• Adds a toolbar button to let you insert the build identifier into the current text box (Not supported in the Application Suite).
• Lets you customise the title bar to include the build identifier and other information.
• Provides talkback integration allowing you to quickly view recent incidents as well as a sidebar that shows all incidents still on your machine (you may be surprised at just how many there are).
• Adds a simple interface for parsing nspr log files for leaks.
• Lets you take a screenshot of any open window and save it as an image, copy it to the clipboard or submit it to Imageshack (not yet fully functional in cairo builds).

If this does not work you can try to tell Firefox which versions of extension to work with by changing the browser’s settings