Monitor Won’t Sleep (Windows 10 or Windows 7)

I've had an issue recently where my monitor won't sleep, and I wanted to share my fix and debugging steps.

Monitor Won't Sleep - Introduction

I was waking up in the morning, any my monitor would still be on from time to time. My power settings were set to turn off the monitor after 15 minutes, so I wasn't sure what was going on.

After reading a few threads, it seemed like something was keeping the monitor on.

This isn't quite security related, but it's a technical issue that's been bothering me for a few weeks now.

Detecting Audio Streams

First, to see what might be keeping my system awake, I used the < href="https://docs.microsoft.com/en-us/windows-hardware/design/device-experiences/powercfg-command-line-options">powercfg command.

As you can see, some sort of audio stream was using my Realtek driver and keeping the system awake.

C:\WINDOWS\system32>powercfg -requests
DISPLAY:
None.

SYSTEM:
[DRIVER] Realtek High Definition Audio (HDAUDIO\FUNC_01&VEN_10EC&DEV_0900&SUBSYS_1458A182&REV_1000\4&11d6fe01&0&0001)
An audio stream is currently in use.

AWAYMODE:
None.

EXECUTION:
None.

PERFBOOST:
None.

ACTIVELOCKSCREEN:
None.

Driver Override

First, to override the power management system, you can use the 'requestsoverride' flag.

In this case, since the Realtek driver was preventing sleep mode, I could use the following command.

powercfg -REQUESTSOVERRIDE DRIVER "Realtek High Definition Audio" SYSTEM

For more information on this command, you can also check out the following post.

Debugging the Issue

While I can override the usage, I wanted to figure out what was actually using my audio streams.

First, I assumed that it might be Chrome, Discord, or a game, but that wasn't the case.

Next, I disabled my microphone, just in case something was using it.

Monitor Won't Sleep - Disabled microphone

When that didn't fix the issue, I started to look at everything that was accessing AudioSes.dll.

Monitor Won't Sleep - AudioSes.dll

Using my very scientific method of killing random processes, my Realtek driver was still in use.

Monitor Won't Sleep - Realtek driver
After finally killing my nvcontainer.exe process, my driver was no longer keeping the system awake!

C:\WINDOWS\system32>powercfg -requests
DISPLAY:
None.

SYSTEM:
None.

AWAYMODE:
None.

EXECUTION:
None.

PERFBOOST:
None.

ACTIVELOCKSCREEN:
None.

I'm not certain what Nvidia was doing exactly, as I wasn't hearing any audio coming from my computer. That said, I now have a better idea of what process might be causing this.

Monitor Won't Sleep - Conclusion

I know this wasn't exactly security related, but I'm still catching up on older posts.

If you have any ideas what nvcontainer.exe might have been doing with an audio stream, then let me know.

For another write-up, I recommend checking out this blog post.

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doyler
Ray Doyle is an avid pentester/security enthusiast/beer connoisseur who has worked in IT for almost 16 years now. From building machines and the software on them, to breaking into them and tearing it all down; he's done it all. To show for it, he has obtained an OSCE, OSCP, eCPPT, GXPN, eWPT, eWPTX, SLAE, eMAPT, Security+, ICAgile CP, ITIL v3 Foundation, and even a sabermetrics certification!

He currently serves as a Senior Staff Adversarial Engineer for Avalara, and his previous position was a Principal Penetration Testing Consultant for Secureworks.

When he's not figuring out what cert to get next or side project to work on, he enjoys playing video games, traveling, and watching sports.

Common passed on this blog, I made it to a jam.

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