I try installing FireBug in FF8, apparently it downloads it correctly, but reports an error when installing. No debug information is shown, just "can't modify the file". How can I debug this installation in Ubuntu (Xubuntu, 11.10)? If it's just user rights issue, it should not be a problem.
Compatibility Firebug 1.9 will work with Firefox 6.0 up to Firefox 9.* (or higher) Firebug 1.8 works with Firefox 5.0 up to Firefox 7.* Firebug 1.7 works with Firefox 3.6 up to Firefox 5.*, see however known issues. Firebug 1.6 works with Firefox 3.6 Firebug 1.5 works with Firefox 3.5 and Firefox 3.6 Firebug 1.4 works with Firefox 3.0 up to Firefox 3.6 (1.4.4) Firebug 1.3 works with Firefox 1.5 (1.3.0) up to Firefox 3.0 Firebug 1.2 works with Firefox 2.0 and Firefox 3.0 Firebug 1.0 works with Firefox 1.5 and Firefox 2.0 Firebug Lite works with IE, Safari, and Opera Please visit AMO for a full version history.  Installing in a clean profile To test for bugs regarding interactions with other extensions or corrupted profiles, you should do the following. Firefox and Firebug re-install rarely fixes problems because the configuration files are not altered on reinstall. So to clear out the configuration files you need to create a new Firefox profile:  Linux Way Exit Firefox Get to a command line Run Firefox with -ProfileManager $ firefox -ProfileManager Create New Profile Start Firefox with your new profile Load Firebug into this clean profile.  Windows Way Exit Firefox Get to a command line Windows: Start->Run->"cmd" enter Run Firefox with -ProfileManager (use quotes around the file name because of the spaces) "C:\Program Files\Mozilla Firefox\firefox.exe" -ProfileManager Create New Profile Start Firefox with your new profile Load Firebug into this clean profile. Read more about this on Mozilla Support "Managing Profiles"  Can't Install Firebug on Windows Sometimes Firebug just won't get installed in Firefox using Windows. The first thing to try is a new Firefox profile above. If that fails you can dig deeper. Here are some recommended actions to take: With Firefox closed, locate your profile directory, delete these temporary files, they will be automatically re-created by Firefox: extensions.ini extensions.cache extensions.rdf compreg.dat Disable any Antivirus or BackUp program you may have running and then install Firebug. It may be that some software is stopping Firefox creating the file structures needed for the installation process. Run Firefox as Administrator. It may be the same as in reason 2, because firefox doesn't have enough permissions. Manually install Firebug. This can be done easily, just unzip the XPI (it's a normal zipped file with the extension changed) in your extensions folder, inside your profile. You should unzip firebug's XPI content inside a folder named 'email@example.com'. Do this with Firefox closed. To get the XPI go to Firebug on Addons.Mozilla.Org, right click on the "Add to Firefox" button and select "Save Link As...".