Disabled add-on compatibility checking a while ago to try forcing some old add-ons to work. I want to re-enable add-on compatibility checking. I've tried doing this from about:config, but the information resets when firefox starts or closes. I tried putting it in user.js, but, even though the file is reloaded as firefox starts, there is no reaction as to the contents of the file. My user.js file follows: (C:\Users\h3X\AppData\Roaming\Mozilla\Firefox\Profiles\airs8akf.default\user.js) // User.js - replaces all prefs set elsewhere in mozilla user_pref("extensions.checkCompatibility", true); user_pref("extensions.checkCompatibility.3.6", true); user_pref("extensions.checkCompatibility.3.6b", true); user_pref("extensions.checkCompatibility.3.6p", true); user_pref("extensions.checkCompatibility.3.6pre", true); user_pref("extensions.checkCompatibility.3.7a", true); user_pref("extensions.checkCompatibility.4.0b", true); user_pref("extensions.checkCompatibility.4.0p", true); user_pref("extensions.checkCompatibility.4.0pre", true); // end