After August update Hyper-v Win10VM crashes when connecting via RDP

A fellow member, not saying who @Bree asked me to check this thread. I am completely unable to reproduce your issue, all my host to VM, VM to VM and even VM to other virtualization hosts RDP connections working without issues. Therefore, I am not able to offer any solution.

However, you could try something. First, be sure both host and guest VM belong to same workgroup, and belong to same subnet.

Then, check that all these services are running on both the host and VM:

• Windows Remote Management
• Remote Access Auto Connection Manager
• Remote Access Connection Manager
• Remote Procedure Call (RPC)
• Remote Procedure Call (RPC) Locator
• Remote Registry

When they are running, run this command on both host and VM in an elevated PowerShell:

Set-Item WSMan:\localhost\Client\TrustedHosts -Value HostPCName,VMPCName

Still in elevated PS, run the following command to add a DWORD value to registry on both host and VM:

REG ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 1

And last, edit FireWall on both host and VM:

Set-NetFirewallRule -Name WINRM-HTTP-In-TCP -RemoteAddress Any

It should work now.

Kari

MontyP said:

Although I couldn't see how checking the services listed and adding the config'n changes would impact on a previously working setup that failed when KB4512508 was applied and again worked once KB4512508 was removed, I, none the less, staged your hit list but to no avail.

Those are all RDP related services, my personal list of stuff I do whenever any issues with it. Has always worked for me.

Sorry for your trouble, don't know what else to suggest.

Kari

Hi there.

@MontyP

might be a bonkers suggestion but could you login to your Windows guest via SSH rather than RDP.

If SSH sign in works presumably you could also use that if your VM is a W10 HOME edition which doesn't allow external computers to RDP into it.

Otherwise I think some type of VNC can run on Windows so instead of RDP try that.

My policy is usually if something is broken then to try and find a "get around" until those much more knowlegeable geeks find the appropriate fix.

Comes from my Engineering background --if something is broken -- get it running ASAP and then do the analysis of why it broke in the first place unless the cause is abundantly clear e.g wrong voltage to a device etc etc.

Download TightVNC

How to Enable and Use Windows 10’s New Built-in SSH Commands

Personally my own preference is for using a Linux Host and run Windows only as Virtual Machines. I use VMWare workstation but there's free VMWare player -- and there's Oracle's Virtual Box free also for non commercial use. These products all have adherents on this Forum. VmWare workstation is a paid product but you can try it for 30 days free (no hobbled features) to see if you like it. It installs on both Windows and Linux - there's loads of decent Linux distros (all free) around so you have to make your own choice on those.

I do have a windows machine though if I really need to use real hardware such as a video capture device which is fiddly on a "para Virtualised" VM as used by VmWare and Oracle - although I'm experimenting with KVM to see if I can get video passthru to work . Paravirtualised VM's use "emulated devices" i.e their own graphics etc so if you actually need access to the actual graphics hardware then that's a problem -- however these days most applications work very well on a VM including quite intensive things like Photoshop etc.

If you want to use something like a HYPERVISOR (akin to Ms's HYPER-V) you can use KVM (built in to most Linux distros) or ESXi - which has the advantage of being a really tiny OS so your VM's can run with native hardware at around 99% performance of the native speed. You can even boot esxi from a micro sd card --once it's booted you don't need the card any more -- a tiny OS which is resident in RAM after booting -- a tiny amount though. However setting up is a bit tricky though.

Here's an example of a VMWare W10 (20 H1 latest skip ahead edition -- testing these builds with VM's is a great idea so it doesn't matter if they break) running on the newest Linux kernel 5.3 on manjaro (similar to archLinux) but almost any distro will work.



If you do "break away from Ms" there are decent Office "clones" around which are quite compatible with Ms office and Thunderbird is quite a reasonable (Free) email client that supports multiple accounts, different email servers, exchange, imap etc so it's reasonably possible to be mainly "ms Free" but some things there aren't any choices but to still have Windows - which is where VM's help a lot.

Cheers
jimbo

Ben Hastings said:

This looks like a known issue with 1903 with latest patches.

As you disconnect from RDP but leave the session open, dwm.exe goes crazy with CPU load. it will take 100% usage of one core.

In Hyper-V Manager this looks like 10-12% if your Hyper-V host has 8 cores.

You can try:this fix:
REG_ADD "HKLM \ SOFTWARE \ Policies \ Microsoft \ Windows NT \ Terminal Services" / v "fEnableWddmDriver" / t REG_DWORD / d 0 / f

found at https://answers.microsoft.com/en-us/...f89837a?page=2

Hi all,

New here, made an account just to respond. I have been running into this issue for a while now: I could connect to a stopped VM, start it, and use it. But as soon as I clicked the X to close the viewer window, I was unable to connect again without force stopping the VM and repeating the process. No amount of command line or other connection methods worked to resolve this.

I got sick of this issue and decided to isolate what was causing it. I built a fresh VM today off of a Win 10 x64 Enterprise, build 1903 .ISO. As soon as the VM let me in, I created a checkpoint. I then proceeded to test disconnecting from the VM and reconnecting successfully using the Hyper-V Manager. I tested pingpong connecting between the Hyper-V Manager's connect and RDP, as well. It appears a completely fresh VM does not exhibit issues.

I proceeded to patch and download Micro$oft 2019-08 Cumulative Updates For Win 10 version 1903 for x64 based systems (KB4512508). IMMEDIATELY after reboot I had connection issues. The only thing I could do to get back into the VM was to choose Turn Off, or do a Shut Down and wait patiently, and then connect to the VM again, and start once I was in the connection window.

So this issue of KB4512508 installing and preventing connections to a clean Win 10 build is totally a thing. Once armed with the knowledge it's this patch causing the issue, it lead me to this thread! Yay!

Testing a few things I read in this thread, I first tried to get into my VM which refused connections by turning off Enhanced Mode connections. Nope, didn't work. But then something in Ben's post got me thinking. If the VM CPU is "pegging" (mine showed 24% usage), why not give the VM more CPU to play with and see what happens? Now I have a bit of an older gaming system; an unlocked Haswell i5, but still going good. I was also prepared to log the CPU usage in case I couldn't get back in. At least I'd have been able to see what was going on when I finally shut down and reconnected.

I shut off the VM, ramped it up from 1 to 3 cores, and turned off the enhanced connection to see what happens. Presto I got in right away. Resuming prior testing, I X'd out of the VM, and then reconnected multiple times. I ping-ponged myself between RDPing in and using the Hyper-V Manager connect to get in. All was good.

Okay but now it's time to do more isolation. Was it the enhanced mode connection, and just a one-off inability to connect? Or was the additional CPU power actually involved? I shut the VM down and took it back to 1 CPU core. Bzzzzt, unable to connect again. I increased it back to 2 and was able to get in. This may explain why this problem manifests for some and not others. Maybe the ones who don't see the issue have enough CPU power allocated either by Hyper-V processor settings, or hardware beefiness, to simply be unaffected, or not realize they too have the issue.

So it definitely looks like for me to get back in, I need to do a combination of non-enhanced mode, and additional CPU power. And I didn't have to roll the patch back and lose system settings, installs, etc. I hope this helps some of you get into VMs you're locked out of, WITHOUT reverts!

But what's the FIX? Because I kinda want to run enhanced mode, and don't want to dedicate so many processors to my main VM.

I ended up doing gpedit.msc and entering what the guy on that webpage said (details below) and now I can pingpong on the VM between RDP and Hypervisor connect, without having to force shut down the VM to reconnect. I am running enhanced mode and 1 processor only in Hyper-V. I implemented the same fix below to both the bare test VM and my main "production" VM and it fixed both. I am beyond elated. And I can keep the patch installed.

Have fun rolling this out to a bunch of production VMs. o_O

PS. I ran into issues skipping steps 1-3 and just making the policy updates. I recommend following the below steps as closely as possible, and be prepared to tweak things.

--- TLDR, I am locked out of my Win 10 Hyper-V VM if I disconnect from it - How do I fix? ---

1. Shut down your VM - force shut it off if you can't wait patiently.

2. Turn off Enhanced Connection mode (Right side of Hyper-V Manager > Hyper-V Settings).

3. Jack up the # cores available to the VM you are unable to connect to - requires the VM to be powered off (In Hyper-V Manager, Right click VM > Settings > Processors > Number of virtual processors)

4. Run gpedit.msc and implement below fix found at this web page: Windows 10 1903 Remote Desktop Probleme

Customize the GPO to use WDDM XDDM for RDP connections:
Local Computer Policy -> Computer Configuration -> Administrative Templates -> Windows Components -> Remote Desktop Services -> Remote Desktop Session Host -> Remote Session Environment -> Using WDDM Remote Desktop Connection Video Drivers -> set to DISABLED

5. (For testing purposes you may want to shut down cleanly at this point and bring it back up)

6. Test to see if you can reconnect to the VM via Hyper-V Manager and other methods (I tested Hyper-V Manager and RDP)

7. Revert the Enhanced Mode and Processor increases for the VM. Just set it back the way they were before you began.

8. You may want to repeat steps 5 & 6 here. If you are satisfied it's working, make a snapshot.

Well this works for me. Thanks Ben for the tips leading me to the answer.

Also I'm looking for Desktop work in San Diego too, if this happens to help anyone in a position to help me. :)

Just an idea.

Instead of Enhanced Mode in Hyper-V, use Windows Admin Center (WAC) to manage and connect to your virtual machines. In screenshot, I am connected to a VM running latest Insider Preview build 18970 in Swedish from WAC:


(Click / tap to enlarge.)

Works perfectly, at least for me.

Kari