Hi aogypn, welcome to the forums.
Open the Resident Scanner, change the setting to High and then click on the Terminate button, from here you will be asked if you want to save your settings, click the Yes button. Now click the Start button, and you will probably be confronted with the same choice, click Yes again.
This has been known to work in some other cases and for me at least, it was a work around for a similar problem.
Give it a try and see if it works for you.
HTH David