How do I delete the "Add-On" pop up box that appears when I start Firefox
Every time I open Firefox a pop up box appears for add-ons. It is blank and does nothing. I close it and other one appears and I close that, then firefox starts. It's not a big thing, but it's a pain. It does not appear when I start IE8.
Opaite Mbohovái (1)
You can try http://kb.mozillazine.org/Preferences_not_saved
You can also try to delete the files extensions.* (extensions.rdf, extensions.cache, extensions.ini, extensions.sqlite) and compatibility.ini in the Firefox profile folder to reset the extensions registry. New files will be created when required.
See "Corrupt extension files": http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
If you see disabled extensions that are not compatible on the next start in "Tools > Add-ons > Extensions" then click the "Find Updates" button to do a compatibility check.