Now obsolete Rated 4 out of 5 stars

This has been a great add on that didn't work with newer versions and isn't updated anymore. I really missed it an now just discovered Firefox 4 has this function build in. So you can either wait 3 months or so until Firefox 4 is officially released or get the beta version. No need for this extension anymore...

Rated 4 out of 5 stars

The new Firefox 4 beta won't let you install the extension. Follow these steps to get it to accept it:

1) Open about:config
2) Right-click and select New -> Boolean
3) Enter this name:
extensions.checkCompatibility.4.0b
4) Set it to false

The extension might still fail to work, but you can at least try it now.

Rated 5 out of 5 stars

Bardolfo and everybody else,

you can set Firefox to accept addons even if they are marked as not-compatible.

1) Open about:config
2) Right-click and select New -> Boolean
3) Enter this name:
extensions.checkCompatibility.3.6
If you're not using 3.6, adjust the number to your version.
4) Set it to false

Every time you update to a new version you have to recreate this setting with a new name to reflect the version change.

Now Fx should accept all add-ons. Even those which might crash the browser and maybe cause serious trouble. So use it wisely.

not working with 3.6a1 Rated 3 out of 5 stars

I tried it with 3.6a1 and it doesn't seem to work. Trying to access the settings for the FTU causes the add-on manager to crash. And there is no FTU entry in the context menu.

Maybe this only happens because of the alpha status of 3.6

But does anyone know of another extension like FTU I could use for now?