A General Discussion would be about something not really connected with McAfee perhaps? A PC problem or a post where someone isn't sure where to post. We would then move it accordingly.
Home and Home Office is merely the header for this entire Consumer Section and although someone could post there, we would no doubt move it, like I have with this thread, to the actual section dealing with that product.
Now the acan, is Scheduled Scan set to go off at a certain time? If so it tries to do that withing a reasonable time from that moment. If you want to be sure it doesn't happen then temporarily turn off Scheduled Scan.
Sometimes, rarely, a scan will be triggered by something happening in the system, but Windows Update shouldn't do that.
Another probability is that , If you have a schedule scan to run on the same date as of you windows update. And during the time if the PC was turned off , scheduled scan would initiate the next time PC is started . So , you can have a check on your schedule scan timings ,