Steven Levine
Steven Levine
~1 min read


If you are like me, and you like to use the latest and greatest software regardless of whether they are GA or not. Then you probably ran across this problem too. After migrating to Firefox 3 Beta, I found that many of the Firefox 2.x plug-ins did not work. I didn’t know this for sure, since Firefox would not even attempt to load them. There is a feature in the Firefox plug in manager that verifies each plug-in is compatible with the current running version of Firefox prior to installing it. There are some plug-ins out there updated to work with FF 3 beta, but many of them have not been updated yet. I found a workaround. Simply add the following value to your config: Here is the procedure:

In the address bar type: about:config (When it asks you to be careful, say you will)

Right Click -> New -> Boolean

In the text field type: extensions.checkCompatibility

  • Note: If you are using Minefield 3.7a, you need to add extensions.checkCompatibility.3.7a instead

Select False

That’s it. Now try installing your favorite Firefox 2.x plug-in.

Disclaimer: This procedure does not guarantee the plug-in will work, only that it will install.