VirusBarrier will not wake your Mac to run a Scan. There are third party Apps available in the Mac App Store to prevent your computer from sleeping such as Caffeine. Please note that Caffeine is not an Intego application and we do not support this software. Apple made a change with the release of Mac OS X Lion that puts the computer to sleep even when it is actively being used. This means that it could potentially go to sleep while the Scan is running. We recommend scheduling a scan when your computer is awake.
Alternatively, you can also change your settings in System Preferences > Energy Saver to prevent your computer from going to sleep. See the images below for instructions: