If you’re using Firefox 4.0 beta, there’s a good chance that some of your extensions are incompatible with the new browser. But don’t worry, there are a few ways to install compatible extensions even if they don’t work in beta. The first way is to use Firefox’s add-on manager. This tool lets you find and install compatible extensions from a variety of sources, including Mozilla and third-party developers. The second way is to search for incompatible extensions on the Firefox Web Store. This store offers a wide range of extension products, so it’s likely that you’ll find some compatible ones there as well. Finally, you can try installing an extension manually. This approach is less reliable but can be useful if you have trouble finding an incompatible extension or if you just want to try out some new features of beta Firefox.
Here’s the error message we’re talking about:
Side note: want to test the new beta out for yourself? Head over to the Firefox Beta site, though it’s really in beta, and has a lot of changes, so you’ll want to think carefully before you do so.
Open up the about:config page, and then right-click anywhere and choose New –> Boolean.
You’ll get a popup menu, at which point you’ll want to use one of the two values as the preference name, depending on the version you’re using:
4.0 Release: extensions.checkCompatibility.4.0
Then set the value to false.
At this point your extensions should install just fine…
Important Note: At the moment of the writing of this article, Greasemonkey is really actually incompatible with Firefox 4.0 beta, and continually opens up the homepage with a never-ending list of tabs. The same goes for quite a few extensions that we tested, though some of them worked fine. We’re pretty sure they’ll be updated very soon.
