I've scheduled my PC to wake from standby mode at 2am weekly to perform a disk defrag, which takes a little over two hours. I've noticed that every half hour, the monitor wakes unnecessarily, until it times out and goes back into standby mode (there is no user input the whole time).The Event Viewer does not show any events that correspond to all the monitor wakings (though the Application Experience did start at the time of one or two of the wakings).Does anyone know why the monitor might be periodically waking unnecessarily, and how that can be prevented?

Hi, If the monitor resumes, there must be some tasks that awakes it. In Event Viewer, check the Kernel-Power related events in system log and there will be some clues. Meanwhile, I suggest that you temporary disable the wireless network adapter and check the result. Also please let us know if you use a wireless keyboard or mouse. Arthur Xie - MSFT

No wireless keyboard or mouse. Wake on LAN is disabled. No Kernel Power events in the system log at the relevant times.(My original description may have been unclear on one point: the periodic monitor wakeups occurred during the scheduled defrag. So the PC itself was properly awake; it's just that there was no need for the monitor to keep waking up.)

Hi, When the monitor wakes, does the system resumed? If not, I suspect that this issue is related to the compatibility between Windows 7 beta and the monitor or video adapter. In this situation, I suggest that you upgrade the video driver. If there are available monitor drivers, upgrade the monitor driver. Then, if the issue still occurs, I am afraid that one of the devices is not compatible with Windows 7 beta.Arthur Xie - MSFT

Hi Arthur. The monitor wakes periodically while the scheduled defrag is running. So yes, the system has resumed. My video card is the GTX 260, and I'm using the latest WDDM 1.1 drivers (181.71, specifically for Windows 7 beta).Except during the scheduled defrag, the monitor sleeps and wakes only when it's supposed to.

There is a command you can run in an administrative command prompt. c:\powercfg -energyThis will generate an HTML report of all the drivers and devices that may be causing issues with power settings. It is pretty technical in nature but it may help isolate the problem.Daniel Nerenberg MCT MCSE MCITP MCTS MVP