You didn't post the extension list of your old profile. It is still possible that (possibly binary) components of an extension were still active for some reason in Safe Mode and that only uninstalling would work. ----- In Firefox Safe mode these changes are effective: *all extensions are disabled (about:addons) *default theme is used (no persona) *userChrome.css and userContent.css are ignored (chrome folder) *default toolbar layout is used (localstore-safe.rdf file) *JavaScript JIT compilers are disabled (about:config page: javascript.options.*jit) *hardware acceleration is disabled (Options > Advanced > General) *plugins are not affected *preferences are not affected