Applies to: Windows Server 2016, 2019, 2022, 2025 with Remote Desktop Services (RDS)

The September 2026 security update from Microsoft introduced an issue affecting Remote Desktop Services (RDS) on Windows Servers. After installing the update, some servers may work normally for a few hours before experiencing connection problems.

You may get stuck on “Connecting…” or “Please wait…” when starting a Remote Desktop session; existing sessions may fail to log off, and in severe cases the server may stop responding and require a manual restart.

Microsoft has released fixes. Below are two recommended options to restore normal operation while retaining security protection.

Step 1: Check whether your server is affected

Reboot the server if not accessible via RDP, then open PowerShell on the server and run:

Get-ComputerInfo | 

    Select-Object WindowsProductName, OsBuildNumber

Get-HotFix | 

    Where-Object HotFixID -Match 'KB5122876|KB5122882|KB5122871|KB5123099|KB5129238|KB5129237|KB5129235'

Example output:

Source Description HotFixID InstalledOn

------ ----------- -------- -----------

SERVER01 Security Update KB5122882 9/9/2026

You are affected if one of the following updates is installed:

If KB5129238, KB5129237 or KB5129235 is already listed, the permanent fix is installed.

Step 2: Choose a solution

Option 1: Install the permanent fix (recommended for 2019, 2022, 2025)

Microsoft released out-of-band (OOB) updates on 14 September 2026. They resolve the issue without removing the September security updates.

These updates are not offered through Windows Update or WSUS by default.

1. Download the update for your Windows Server version from the Microsoft Update Catalog. If you use WSUS, import it there instead.
2. Install it on the affected server.
3. Restart the server during a scheduled maintenance window.

Note: Restarting disconnects all active Remote Desktop sessions.

Option 2: Apply Microsoft’s Known Issue Rollback (KIR)

Microsoft has not released an OOB update for Windows Server 2016, so the recommended alternative is the Known Issue Rollback (KIR). KIR reverses the faulty change and keeps the security patches. It is also a fallback for 2019, 2022 and 2025 if the permanent fix can’t be deployed yet.

1. Download the appropriate Known Issue Rollback (KIR) MSI package for your Windows Server version from the Microsoft Update Catalog.

2. Install the downloaded MSI package directly on your affected server.

3. Navigate to Computer Configuration -> Administrative Templates and locate the relevant Known Issue Rollback policy for the affected update.

4. Set the policy to Disabled, as specified in Microsoft's instructions.

5. Run the following command in an elevated Command Prompt or PowerShell window to apply the policy: 

gpupdate /force

6. Verify that Remote Desktop connections and user logoffs work normally.

Note: If the KIR policy does not appear after installing the MSI, ensure that the required policy templates are installed correctly.

Summary

If your Remote Desktop environment is affected by the September 2026 update, install the permanent out-of-band update where available. For Windows Server 2016, use Microsoft's Known Issue Rollback as the preferred workaround.

Both options restore reliable Remote Desktop access while preserving the September security patches. If you have any further questions, please contact our support team.