Five Hour Plus Boot Time Scan

This is my first boot time scan using Avast 5.0.462. My Vista laptop has been running the scan for over five hours.

The scan appears to be working normally, but in the past, a scan would run an hour at the longest.

Is this normal?

Without knowing your settings and how much data there is to scan, it’s impossible to tell.
(Your settings also greatly influence how much needs to be scanned. )