Hi Tuxedo, are these normal downloads or custom protocol links (like zoommtg:, magnet:, etc.)? For normal downloads: where does this intruder first appear? (1) If this appears instead of the usual download dialog. I would suspect one of your extensions, although I couldn't tell you which one it is. Try disabling all the ones you can live without for two hours and see whether that changes anything. (2) If this has taken over as the default to open a document in the download dialog Change your setting on the Preferences page. See: [[Change what Firefox does when you click on or download a file]]. ''If it is a custom protocol link, the instructions also can be found in this dialog.'' Also, check for the unwanted program on your system. (3) If this has taken over as the default system application when you launch a download from Firefox's Downloads list This is a system setting.