Removing browser add-on

Avast Browser Clean-Up recommends removal of an add-on. when clicking ‘remove’ a pop up informs me that i do not have administrator privileges and must go to the desktop icon, right-click and select “run as adminstrator” and restart the application. I’ve tried that 4 times and the same message still comes up after re-starting Avast. Any ideas?

https://forum.avast.com/index.php?board=54.0