sicherlich mein ich "extensions" 
Corrupt extension files
Files that store information about the extensions you have installed can sometimes be corrupted. Deleting them can fix a number of extension issues; they will be regenerated the next time you start Firefox. [17][18]. Exit Firefox completely, then open your Firefox profile folder (read the linked article for its location) and delete* these three files:extensions.ini
extensions.cache
extensions.rdf
hat funktioniert 
kann zu Danke für die schnelle Hilfe 
MySt3rY
