igor0
8
The behavior has nothing to do with the file you are rightclicking on.
When you rightclick, Windows is loading the modules responsible for the context menu - not only avast’s, but also other programs (which can get rather big if you have other tools installed that put themselves into the context menu).
So avast! is just scanning the programs being loaded at that moment.
I’m afraid I don’t see how reinstall could change anything here.