Avast Scans External Drive

Hi there,
When I do a full system scan Avast scans my external USB drive that I use for Time Machine.

On the settings of On Demand Scans there is nothing checked off under:
Scan Also Mounted Removable Volumes.

How do I prevent Avast from doing this? Thanks.
~Verne~

Hi There,
First of all thanks for the NO HELP!

I figgured it our for myself by doing my backups, Time Machine etc… then ejecting the external drives.

Turn off the power on the USB/Thunderbolt drives THEN doing the full scan and it worked!!
~Verne~