1- make sure that "Use Scan Windows" isn't selected. If you use Scan Windows, your scan will only run during the hours you specify on the day(s) you have it scheduled and if it didn't finish, the scan will continue the next week.
2- Has the scanning completed before the next scan schedule starts? This can be another reason.
Hope this helps.
If you're still having problems with your scheduled scans, please open a Service Request:
For contact details:
- Go to: http://www.mcafee.com/us/about/contact/index.html
- Non-US customers - select your country from the list of Worldwide Offices.
Log in to the ServicePortal at: https://mysupport.mcafee.com:
- If you are a registered user, type your User Id and Password and click OK.
- If you are not a registered user, click New User and complete the required fields. Your password and login instructions will be emailed to you.