"1 new add-on has been installed" After FF4 Uninstall

I was running FF 3.6.15 and replaced it with FF4 a couple of days ago. A number of my add-ons were not compatible with FF4 so I uninstalled it and installed 3.6.16. Now it takes at least a minute for FF 3.6.16 to load (if it does) and I always get the add-on dialog box indicating that 1 new add-on has been installed. Sometimes FF starts but the GUI does not show on the screen. No new add-ons have been installed.

I believe this problem is a result of having installed FF4 which has a different way of handling add-ons.

Anyone have a solution?

I run my browsers Sandboxed (Sandboxie) with DW3 and Panda Cloud Pro.

 

Did you make sure you deleted everything left behind by FF4 and the previous install? I had extremely screwy issues when I went from 3 to 4, and then the next Beta. I just wiped it all, registry entries, files, profile and started over.

 

I may have to do this, but I would prefer to do something less drastic if I can.

 

I'm wondering if some profile files have been changed by FF4, the pref.js file for instance?

@chinook9
Does FF 3.6 work OK if you create a new profile (run firefox.exe -p)?

 

I don't know what kind of backup strategy you have but if a recent copy of your Firefox 3 profile is included in any of your backups, you could simply delete the contents of the profile folder and replace it with the one from your most recent backup. You might lose a few changes but it could be quicker and easier than recreating a new profile from scratch.

 

Thank you for the recommendations. It looks as though the problem is solved.

I tried sbseven's recommended and the new profile did solve the problem, however, the new profile did not have my add-ons or bookmarks.

I went into the old profile and copied the bookmarks over to the new profile, then I installed WOT, NoScript, and Keyscrambler. Now I'm pretty much back to where I want to be.

Thank you again for the help.