Citrix and Microsoft have identified an issue when launching seamless applications from a Server VDA running Windows Server 2016. When a user launches an application published from this VDA, Citrix Receiver displays a black screen covering the work space of the monitor for several seconds before launching the application.

Citrix and Microsoft have worked together to deliver code fixes for both Windows Server 2016 and XenApp.

Microsoft is targeting their patch for the third week of August (KB4034661, which will be available via the Microsoft^®Update Catalog). We will include our fix in XenApp 7.15 LTSR, available here: https://www.citrix.com/downloads/xenapp-and-xendesktop/.

Note: Both fixes are required to resolve this issue.

It requires a registry edit to enable.

Navigate to: HKLM\SOFTWARE\Citrix\Citrix Virtual Desktop Agent
And then create the following registry value (value type = REG_DWORD): DisableLogonUISuppression 
0 - Feature enabled (LOGON UI SUPPRESSION – No Black Screen)
1 - Feature disabled (You will see the Black screen issue).

There is also a patch available for XenApp 7.14. You can find installation instructions below

7.14 Installation Instructions

1. Download the zip file.
2. Extract the rpm.dll from ZIP file
3. On the Server VDA, navigate to C:\Program Files (x86)\Citrix\System32
4. Rename rpm.dll to rpm.dll.bak to back up the original version of rpm.dll
5. Copy the patched rpm.dll to C:\Program Files (x86)\Citrix\System32
6. Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\Citrix Virtual Desktop Agent
7. Create the following registry value:
   • (value type = REG_DWORD): DisableLogonUISuppression
   • Value= 0
8. Reboot the Server VDA.

Citrix and Microsoft identified issues surround the ThinWire remoting of the LogonUI component in Server 2016.

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