The Forecastfox extension won't work with this program. I think it probably has something to do with the extension popping up a dialog box the first time you open Firefox after installing it. Whenever I open Firefox after using the silent installer with Forecastfox in it I get the attached error message and I have to go past it twice every time I open Firefox. It wasn't much fun uninstalling and reinstalling Firefox to figure this out but now I know. I've got my core extensions so it should be a problem for me in the future. I just wanted to warn anyone else who might come upon this problem. If I'd been smarter I would have just removed extensions from within Firefox until I found the offending one but I suppose hindsight is 20/20 So yes, If you install an extension that does something like this removing it in Firefox will fix the problem.