MessageIt has been a while sense I had that program but, I believe, if your computer is on and not being used by yourself, the scanning program will conduct the schedule scan. If you are writing say a paper, during the time for the scan I think it will wait. Like right now, my scanning program is scanning the computer even though I am writing a message. It is a good idea to have it checked because, if your typing or running the web, your computer may become slow with all the tasks going on at the same time. Heather