Well this is were it becomes tricky. I have 2 systemextentions left on my mac. They are leftovers from an antivirus software that I uninstalled using the only available method - which is and uninstall solution build by the antivirus company. This is all good, but I'm left with these 2 extensions. Now the question is - how do I get rid of them ? According to this thread, the only supported way is to drag the parent application to the trash. This is not an option as the app is no longer installed. I no longer have a license for it, so reinstalling is not an option. @Apple - As an OS supplier, you must be concerned about security, and having these different leftovers left in the system, that is no longer updated by the manufacturer cannot be good for security. There must be a way to uninstall them manually ?