Why does my McAfee scheduled scan take a long time to complete?
The setting “Scan Using Minimal Resources” is enabled by default, and limits the speed of a scan. You can disable this behaviour on the Schedule Your Scan options page. Your scan times will decrease, but your computer could be very slow for the duration of the scan, so this is only recommended if your scan is scheduled to run overnight. You can also exclude or disconnect external hard rivers and network drives from your scan.
Why doesn't my McAfee scheduled scan start at the requested time?
If your computer is turned off, in standby mode, or in hibernate mode when a scan is scheduled to begin, the scan will be delayed until the next time the computer is on and idle. By default, McAfee is set to only run scheduled scans when the computer is considered to be idle, and laptops need to be plugged into power for the scheduled scan to begin — but both of these settings can be changed.
To force scans to start at the requested time, if the computer is on:
Open McAfee Security Center.
Click Navigation on the right side of the screen.
Click General Settings and Alerts on the left of the navigation options screen.
Click General Settings.
Uncheck the Wait until my PC is idle to run... option.