You might be trying to open Firefox as administrator. If that is the case then this question has been answered previously ([https://support.mozilla.org/de/questions/753537 check out the original answer]). # Right-click Firefox icon. # Select ''Properties'' # Select ''Compatibility'' tab # Check that ''Run program as administrator'' is '''not''' selected If it doesn't change then, try following step: # Check Properties of Firefox.exe (same process as above) ''If you cannot change these settings, restart your Windows Explorer as administrator.''