August 17, 2011 - Warren Held

Force Extension Compatibility in Firefox

Every time a major Firefox update is released and I go to install it I sit there, fingers crossed, as it checks all my plugins for compatibility.  Most of the extensions I use are kept up to date, often supporting versions of Firefox that aren’t out of beta yet.  When I upgraded from Firefox 5 to Firefox 6, however, my ReloadEvery plugin was listed as incompatible.  I use ReloadEvery to automatically reload stock or forex news website tabs every 5 min so I can always switch to the site and have the newest posts visible, without having to manually refresh them each time.  I figured since Firefox 6 wasn’t a major update, the ReloadEvery extension would probably be compatible, it just wasn’t yet listed as officially supporting version 6.  There is a method build into Firefox that allows you to disable the compatibility checking:

  1. Open Firefox and in your URL bar type about:config and hit enter.
  2. A warning is displayed, just tell Firefox everything will be ok.
    About:Config Warning
  3. Type “extensions” into the filter text field to bring up a list of extensions.CheckCompatibility options.  Find the one for the version of Firefox you are using (you can find what version of Firefox you have by going into the Firefox menu -> Help -> About), right click on it, and click toggle.  It should now be listed as false.  You will have to restart Firefox for your update to take effect.
  4. If for whatever reason your extension REALLY wasn’t compatible at all with Firefox, and renders it unusable to the point where you can’t get back in the about:config to turn checkCompatibility back on, there is another way.  You can usually find your Firefox profile by browsing to about:support and clicking on the “Open Containing Folder” button, but if you rendered your Firefox unusable this obviously isn’t going to work.  Instead to go your search bar (Windows 7 just click on the Windows button at the bottom left of your screen, Windows XP go to Start -> Run) enter %APPDATA%MozillaFirefoxProfiles and hit enter.
  5. Once in your Firefox profile folder, locate prefs.js, right click on it, and go to Open With -> Notepad.  Locate the line you modified (in my case it would be user_pref(“extensions.checkCompatibility.6.0”, false);) and change the false to true.  Save and exit.  Now when you start Firefox compatibility checking should be re-enabled.

Firefox firefox / tricks /