Windows 10: September Windows Server Updates Break Remote Desktop Services Across 2019, 2022, and 2025

Windows administrators have reported that the September 2026 cumulative updates are leading to failures of Remote Desktop Services (RDS) on Windows Server 2019, 2022, and 2025, which stops users from being able to connect and, in a number of instances, necessitates a hard reset in order to get the service working again.

These issues occur after the September 2026 Patch Tuesday cumulative updates have been installed, with the servers having worked normally for a few hours before the connection failures begin.

Microsoft has stated that it is aware of these reports and is carrying out an investigation. Going back to the September updates will restore the functionality but will also mean that this month's security patches are removed.

Windows Server RDS Failures and the Suspected Deadlock


As reported by the administrators, the RDS servers function normally for a few hours following the update before connection problems begin to occur; after a server has started to fail, the existing Remote Desktop sessions will not be able to disconnect or log off correctly, and new connection attempts will hang during the connection process before ultimately failing.

A number of administrators have reported that their Terminal Servers were starting to suffer the same problems. "In our environment all of the terminal servers fail (sessions drop, no new connections can be made, the only solution is to carry out a hard reset) within a day," one reader wrote.

Another stated that Remote Desktop Services functioned at first but started to fail after users had logged out: "It works at first, but after the first log out the services crash and no further users can sign in."

In that case, restarting the server made no difference, but the problems were resolved by rolling back the September update.

An administrator who was looking into the issue with Server 2022 stated that the RDP service became unresponsive when users started logging out, and mentioned that debugging had revealed what looked like a deadlock between Remote Desktop and the Local Session Manager.

The post states that the service is stuck at RDPSERVERBASE!WDLIB_Close and that no timeout has been set here, which causes a deadlock between RDP and LSM; Microsoft has not confirmed this as the cause.

Affected Windows Server Updates and the Current Workaround


The reports affect all current Windows Server releases, with administrators reporting similar problems on:

• Server 2019 (KB5122876)
• Server 2022 (KB5122882)
• Server 2025 (KB5122871)

Administrators facing the RDS failures have a limited workaround while Microsoft investigates:

1. On the servers in question, revert the September update, as the administrators say this will restore Remote Desktop functionality.
2. When weighing the option, remember that deleting the update will also mean losing the security patches included in this month's Patch Tuesday release.
3. Keep an eye on the affected servers since it's possible that they will carry on working for a few hours before connections start to fail.

Microsoft is aware of the reports and is investigating, with the intention of releasing guidance when it becomes available.

For now, the only method that has been reported as being able to restore Remote Desktop functionality is to roll back the September update, although this means giving up the security patches for that month.

Microsoft has not confirmed the deadlock theory nor has it given a timeline for when a resolution will take place.

Thank you for being a Ghacks reader. The post September Windows Server Updates Break Remote Desktop Services Across 2019, 2022, and 2025 appeared first on gHacks.

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Remote Desktop Services 2019 generally available Windows Server 2019

Source: Remote Desktop Services 2019 generally available with Windows Server 2019 - Windows Server Blog

 

Remote Desktop Services 2019 generally available Windows Server 2019

Source: Remote Desktop Services 2019 generally available with Windows Server 2019 - Windows Server Blog

 

If I have Windows Server 2022 installed, can I use Windows Server 2019 User CALs? Please note this is not RDS CALs.

According to a post on superuser.com, Windows Server 2019 and Windows Server 2022 are licensed independently. So if you have Windows Server 2022 installed, you can only use Windows Server 2022 RDS User Cals.