Just to be clear, I’m talking about the 3rd party software updater module found under “Statistics>Component Status”. The centre box is the 3rd party Software Updater. Disabling this cured my unwanted scanning. In my case the scanning was related to Avast searching for any 3rd party software that required an update. The scanning of this process was triggering the ondemand module of Avast to scan every accessed file. This would keep my system very busy to say the least.

Since i disabled the 3rd party Software Updater all is calm. ;D

This may or may not be the issue with your system. I just wanted to make sure that you disabled the correct module. 8)