Citrix is actively monitoring multiple reported issues following the installation of the Windows September 2026 Rollup Update on Windows Server and client OS based Virtual Delivery Agents (VDAs).

Reported issues currently include:

1) New connections start hanging a few hours after reboot with "Connecting..." and existing users are unable to log off

The following signatures are indicative of this particular issue:

• TerminalServices-RemoteConnectionManager Event 20498: “Remote Desktop Services has taken too long to complete the client connection”
• Winlogon Event 6005: “The winlogon notification subscriber SessionEnv is taking long time to handle the notification event (Disconnect)”
• TermService status: StopPending rather than Running

2) Black Screens on Login after installing KB5124008 / KB5120998 on Desktop OS VDAs

Microsoft has provided following guidance for now: 

Microsoft provided Known Issue Rollback (KIR) patch for the OSes & they are available at the following links:  

Server OS KIR patches 

Serv 2016: Windows 10 1607 and Windows Server 2016 KB5123099 260911_18473 Group Policy 
Serv 2019: Windows 10 1809 and Windows Server 2019 KB5122876 260911_18474 Group policy 
Serv 2022: Windows Server 2022 KB5122882 260911_18471 Group Policy 
Serv 2025: Windows Server 2025 KB5122871 260911_18472 Group Policy 

Windows 11 KIR patches  

• Download for Windows 11 22H2 and Windows 11 23H2: Windows 11 22H2 KB5122880 260912_00473 Group Policy 

• Download for Windows 11 24H2 and Windows 11 25H2: Windows 11 24H2, Windows 11 25H2 and Windows Server 2025 KB5124008 260912_00472 Group policy 

• Download for Windows 11 26H1: Windows 11 26H1 KB5124012 260912_00471 Group Policy 

 Apply the Microsoft Known Issue Rollback (KIR) patch to the local VDA: 

1. Download & install the respective KIR patch to the effected VDA
2. Now, on the same VDA, launch gpedit.msc and navigate through Local Computer Policy --> Computer Configuration --> Administrative Templates --> KB5xxxxxxxx Known Issue rollback --> Windows OS --> KB5xxxxxxxxx Known Issue rollback, and disable the update.
3. After rebooting, you will be able to establish the connections. 

 Apply Microsoft Known Issue Rollback (KIR) patch using Group policy: 

For enterprise-managed devices that have installed the affected update and are experiencing this issue, IT administrators can mitigate the impact by installing and configuring the designated Group Policy. The policy can be found under Computer Configuration > Administrative Templates > 

https://learn.microsoft.com/en-us/troubleshoot/windows-client/group-policy/use-group-policy-to-deploy-known-issue-rollback 

If there are further updates, we will modify this article.  

Citrix is actively monitoring multiple reported issues following the installation of the Windows September 2026 Rollup Update on Windows Server and client OS based Virtual Delivery Agents (VDAs).

Reported issues currently include:

1) New connections start hanging a few hours after reboot with "Connecting..." and existing users are unable to log off

2) Black Screens on Login after installing KB5124008 / KB5120998 on Desktop OS VDAs