How to override the built-in Add-ons Compatibility Check
Compatibility 
Works with: Firefox 3.6+
Background
With Firefox 3.6, Mozilla has changed the way users can override the default add-ons compatibility check.
The Tweak
WARNING: Bypassing the built-in add-ons compatibility check thus forcing Firefox to allow the installation of incompatible add-ons can cause Firefox to become unstable and/or run erratically. In some instances, could cause Firefox not start at all. In the event forcing an add-on to install has lead to Firefox perpetually crashing upon startup the browser can be run in Safe Mode, which will allow for the removal of the problematic add-on.
Install the Add-on Compatibility Reporter and restart Firefox two times.
Notes
Updated: November 15, 2025
