![Laughing :lol:](./images/smilies/icon_lol.gif)
Anyway, my living room HTPC was working perfectly until recently, when it would constantly wake back up, often just moments after I put it to sleep. Over the course of a few hours, I would see it go back to sleep, wake up again, and sleep again. It's pretty easy to notice it waking up as I can hear the screech of the Blu-ray drive spinning up, and the big blue power ring on the case lights up. The worst part is that the next day, the PC would be misbehaving (typically not responding to the remote control) and I'd have to reboot it to clear things up. This would also often get the power On/Off state out of sync with the remote. So this is more than just an annoyance, this inability for the PC to stay asleep was creating real usability issues.
Anyway, this problem has cropped up for me about a half dozen times over the years, on different PC builds. And after detective work, the problem always has the same root cause - Wake On LAN.
Even though I don't use Wake On LAN (other than when I'm testing that feature out for CMC users), apparently I have some devices in the house that send out Magic Packets or some type of signal to wake other network devices. No idea what is sending out the wake commands, but the solution is to turn off WOL type functionality in the PC that is waking up.
Open the Properties for your network card, click Configure, and then go to the Advanced tab:
Scroll down to the "Wake on..." section, and turn off all you don't need. I think Ping is probably the worst offender, as I probably have another device in the house sending out pings to map the network or something, and the HTPC wakes up in response. I would notice that the HTPC would wake up at specific frequencies, often at the same time (i.e. 9pm, 9:15pm, 9:30pm, etc.).
My best guess is that a recent Windows update or driver update changed this setting, as this was not a problem on my current HTPC until just recently.
With all of those settings turned off, now my HTPC stays asleep. Even better, when I wake it up the next day to watch something, it's ready to go and doesn't have all the issues I was encountering previously. Yay! I guess constantly sleeping and waking up a PC a hundred times a day causes it to freak out a bit.
Hope this helps someone else.
Note, there can be many reasons for a PC to wake from sleep, and if you are having these issues and the above solution doesn't work, then google for the command to check what caused your PC to wake from sleep. That's how I troubleshot this each time over the past decade. Essentially, you'll open up an elevated command prompt window and run the command powercfg/lastwake, which will probably return nothing the first time, but leave this window open and then put your PC to sleep. As soon as it wakes back up, run the command again, and you should get your answer.
Here's a link with details: Why Does My Computer Keep Waking From Sleep Mode?