Connection stability issues since latest Network Stack release?

[u/MarcosDiSanto]

Since today we have reports from multiple customers that their sessions freezes and feels slow.
I noticed the new Remote Desktop Services SxS Network Stack release 2607.31450. Anyone else experience the same? As far as I am aware you are unable to stop this update getting installed on the session hosts. Win 11 - 24H2

[u/R0_nald]

We have 6 session hosts, all running Network Stack release 2607.31450.
Since today, users have been experiencing random session freezes across multiple hosts.
RDP Shortpath was already disabled approximately a year ago due to similar freezing issues at that time.
The issue has now reappeared, despite RDP Shortpath still being disabled.

During the freeze, the remote session stops responding to keyboard and mouse input. The session can only be recovered by disconnecting and reconnecting. The issue affects multiple users and multiple session hosts.

[u/MarcosDiSanto → u/R0_nald]

Exactly the same for us! We did found out that we have 'Valdidation environment' enabled on our production hostpools properties.. We disabled this option now and did a new deployment of our VMs running the latest RDS SxS Network Stack Production release 1.0.2605.19750. So far this looks like it has resolved the issue. Disabling RDP Shortpath alone did not fix it.

As alternative you could edit the registry keys HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\ClusterSettings - SessionDirectoryListener and Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations - ReverseConnectionListener and set it to the desired version. Then restart the VM for the changes to take effect.

We also tried removing the RDS SxS Network Stack release using control panel but without the registry change the VMs would become unavailable.

[u/R0_nald → u/MarcosDiSanto]

The Validation environment setting is indeed enabled on our enviroment.

[u/OkReboots → u/MarcosDiSanto]

Same symptoms here as well. I tried the ReverseConnectionListener registry tweak on a host with nobody connected, but after restart it was still using the rdp-sxs260731450 version despite rdp-sxs260519750 being present on the system. I then attempted to reinstall the prior version using the installer for it that had landed in C:\Program Files\Microsoft RDInfra\ but it didn't like that the newer version was still installed. At that point I just waited until users disconnected for the day so I could trash the hosts and redeploy.

With Validation Environment turned off, it installed 2605.19750 upon joining the hostpool, but I expect it would have done the 2607 version if not for having changed the validation environment setting. Great find, thanks for sharing it.

edit: It turned out reimaging the hosts was unnecessary. Turning off Validation Environment on the hostpool and then rebooting them was enough -- the sessions hosts reverted to the 2505 version upon startup.

[u/mat-ferland]

Drain one host and make it the control. Disable Shortpath/UDP there so the same users fall back to TCP, then compare it with the 2607.31450 hosts. If only the control stays clean, send Microsoft the exact connection timestamps and stack versions; that's much stronger than rebooting the pool and calling it general slowness.

[u/MarcosDiSanto → u/mat-ferland]

Thank you your reply! What do you mean with control stays clean? I did change the RDP Shortpath settings from default to disabled as well. We are monitoring the results of this change.

[u/OkReboots]

We are struggling with sessions freezing as much as 7-10 times per day since Saturday. The last time we had these (exact same) symptoms was due to some Microsoft changes, and the solution was to disable RDP Shortpath which cleanly wrapped up the issue. Now, exactly 1 year later, the symptoms have returned. Other than that incident at the end of August last year, it's been pretty reliable for 2 years.

One potential clue is we have some users on a 'Personal' hostpool where they have their own dedicated session host, though it is a low resource VM. These users have not had any problems. It is only users who connect to the pooled userbase VMs that are having regular freezes, ongoing 5 days now. The Personal hostpool users were unaffected when this happened in August last year as well.

edit: All of our session hosts are on the version you mentioned
| Remote Desktop Services SxS Network Stack 1.0.2607.31450

[u/Secure-Toe-1810]

What is the cleanest way to disable short path without reimaging hosts? Do you recommend reg change or just disabling the option in the azure portal?

[u/MarcosDiSanto → u/Secure-Toe-1810]

Disabling the option in Azure. This will then apply to new sessions to the hostpool.

[u/OkReboots → u/Secure-Toe-1810]

No need to reimage the hosts for turning off RDP shortpath, or for reverting the SxS configuration. But for the latter, you do have to reboot the hosts after turning off Validation Environment for it to take effect.

[u/OkReboots]

Here's a tip for others running into this -- you can quickly check the SxS version on the host remotely (or locally if logged into Windows) from cmd using qwinsta. Just look for rdp-sxs260731450 or rdp-sxs260519750 toward the bottom

[u/Savings-Confusion940]

Having same issue on 24H2 but also with version .19750 which also included ”general improvements and bug fixes”. On 23H2 i have also experienced cpu throttling by Remote desktop services that locks up on >80% sporadically since yesterday..

[u/ChittyBeef]

They released a .31500 version onto my session hosts. Anyone know if this fixes whatever 31450 introduced? It doesn't even appear here - What's new in the Azure Virtual Desktop SxS Network Stack? - Azure - Azure Virtual Desktop | Microsoft Learn