On Windows 10 (1903) I have installed Hyper-V host. On that host I have some Windows 10 (1903) machines. Everything fresh installed. The machines does not yet have any heavy services set up (mostly clean domain joined Win 10). The problem is affecting all the machines the same way.

When the virtual machines starts it has low CPU usage (usually showing 0% in Hyper-V Manager). When I log in the machine after a while it is around 0% again. This is ok. But when I close the session (without logging user off), the CPU usage raises to 12 % and stays there forever.

12 % is because I have 8 logical processors, so one logical processor is 100 % used by the virtual machine.

This 12 % thing happens only when I close enhanced session without logging in. When I am logged in with running session or logged out it never happens. If I close basic (not enhanced) session without logging out it does not happen.

Does anybody know what to do with this? Or at least where to look for causes of the problem?

It is really weird because it never happens when connected so I have limited options to investigate.

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  • i suggest to view for any processes thst keep running, bevause its nszurr of Windows as long as you are beeing logged in all services are armed and ready to rumble, moreover try only to assign physical core numbers as i seen in the past that reduced the load to the host and the wired thing itself the sever was better responding – djdomi Aug 23 '19 at 5:07
  • When you say raises to 12 % and stays there forever, does that mean that if you log-in again the CPU is still stuck at 12% ? – Swisstone Aug 23 '19 at 20:06
  • No, when I log in, it falls to 0%. When I close the session windows without logging out it comes back to 12%. – Martin Volek Aug 24 '19 at 8:40
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    After using Process Explorer I think that the high CPU usage is caused by dwm.exe (Desktop Window Manager). – Martin Volek Aug 29 '19 at 12:28

I have exactly the same problem. Both my Windows host as well as the VM were updated to version 1903. As it is on a brand new laptop I can't tell if the 1903 installation triggered the problems. But I had a simple but unlicensed VM running the 1809 version. This seems to stay running whatever I do.

So right now I'm installing another VM without updating to version 1903. Hope that helps.

Edit: After installation of a new VM without the 1903 update everything looks fine. I've installed MS Office, Dropbox and Firefox. I can minimize and disconnect without any problems. Unfortunately my original VM was updated more than 10 days ago so I can't roll back anymore.

Let's hope someone comes up with a better solution than mine.


I have/had the same issue where I connect to the VM and if I disconnect, I cannot connect again and have to hard shut it down and restart it to get back in. One thing that did help me was that I was running the VM with only one vCPU which meant that once it went to 100% there was no other option but to shut it off. I increased the vCPU count to 2 and I am now able to disconnect and then reconnect without powering off the VM. What is still an issue is after my host goes to sleep with the VM running; upon powering back up, I can get the login prompt for the VM however the logon does not complete and I have to attempt to reconnect again, I was able to get into the VM on the second attempt.

Perhaps others can try this and confirm if it works for them.



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