The speed at which McAfee VirusScan can scan your computer's hard drive and registry depends greatly upon your available system resources. If a wide variety of programs are open at the time of a scan, the time it takes McAfee to complete said scan will slow down dramatically. You can speed up McAfee using a native Windows operating system application called the Task Manager.
Right-click the task bar.
Click "Start Task Manager."
Click the "Applications" tab to view a list of all applications, including McAfee VirusScan, that are currently running.
Close any applications in this window that are not McAfee VirusScan by clicking the program's name and then clicking "End Task." This will free up the available system memory that these programs were using, which will now be available to McAfee VirusScan. This will in turn increase the speed of the McAfee scan as it goes on with your computer.