If you’ve upgraded from Firefox 4 to 5 with Google Toolbar installed, you’ll find Google Toolbar won’t be compatible with Firefox 5, hence it will be disabled. The bad news for Google Toolbar users is that Google ended its support for their toolbar from Firefox 5 and its future versions (may be we need to blame Mozilla’s rapid release cycle which doesn’t give enough time for developers to make their add-ons compatible with Firefox) and Google Toolbar only works now in Firefox 4.0 or its below versions.
If you don’t want to downgrade to Firefox 4 for the sake of Google Toolbar due to security reasons and still want to use Google Toolbar in Firefox 5, this article will help.
Making Google Toolbar Compatible with Firefox 5
Simple just install Add-on Compatibility Reporter and enable Google Toolbar extension in Firefox 5.
#2. Without installing Add-on Compatibility Reporter you can use Google toolbar in Firefox latest version, but this method bit tedious.
All you need to do navigate to this folder C:\users\username\appdata\Roaming\Mozilla\Firefox\Profiles\prifle.default in [Windows 7].
Search for “Install.rdf” file, Windows shows install.rdf files for installed extensions in search results, you need to be patient to open each file in Notepad and check that file related to Google Toolbar if found, change maxversion number to 6.0 from 4.0 (check the screenshot below) and Save the fie.
Now open Firefox, Google Toolbar will be automatically enabled and shown below the Navigation toolbar.
I tested both methods and both enabled Google Toolbar in Firefox 5.