''dupe of https://support.mozilla.org/en-US/questions/1274001'' Firefox works on 3 user accounts, on the 4th on launch a dialog box opens and asks for the Administrator to sign in to approve the installation of a helper. The helper is not named. If you close the box, Firefox locks up. The Administrator signing in closed the box, but Firefox locks up, force quit and the box comes back. Tips, hints or advice welcome.