Yes. I'm using 4.8
Then check this - What avast processes are running in Task Manager, they begin with ash or asw, see image (click to enlarge), ashServ.exe being the main scanning engine and needs to be running. ?
Left click the avast icon, and the on-access scanner window opens.
- click the Details... >> button if it is showing.
- now you should see all the individual shields, the Standard Shield is the resident scanner and needs to be running.