A: When a machine wakes from sleep, an Event Log is written to the System log, Event ID 1, with a source of Power-Troubleshooter, which tells the source of the wake-up.
In the example below, you can see it’s the MED-V Guest Wakeup scheduled task. To stop this wake-up in the future, I would modify this scheduled task to not wake the machine.
Log Name: System
Date: 10/30/2011 11:59:48 PM
Event ID: 1
Task Category: None
User: LOCAL SERVICE
The system has resumed from sleep.
Sleep Time: 2011-10-31T01:29:37.685300500Z
Wake Time: 2011-10-31T04:59:47.972820600Z
Wake Source: Timer - Task Scheduler will execute '\MED V Guest Wakeup - Scheduled Task - john@SAVILLTECH' task.
To see more FAQs, please go to John Savill's FAQs page on Windows IT Pro.