User Launch failures may be seen on the VDA versions 2303 and 2305 if the VDA machines are brought up on-demand for the launch. The initial launch may fail but the subsequent launch attempt after a wait succeeds. VDA de-registration event would be seen following the failed launch.

Symptoms / Signature:

• VDA versions 2303 and 2305

• End users may see a “Resource Not Available” message for the failed launch attempt.

• VDA de-registration event would be seen following the failed launch attempt and the reason displayed for the de-registration would be “RegistrationStateMismatch”

• Issue Signature for confirmation: VDA CDF traces covering the launch failure would report the below trace from the BrokerAgent module -  LaunchManager.PrepareSession(<GUID>): Waited long enough to switch to registered mode, but did not happen

IMPORTANT:  If this workaround was used or is being used, it's recommended to revert the registry key and follow instruction in User launch failures seen on VDA 2303 and 2305 when VDA brought up upon user launch request instead.

1. For “Random” VDAs –

a. Disable the “MachineCreationServicesPlugin” on the MasterImage through the below registry setting:

Registry Location: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\VirtualDesktopAgent\Plugins\MachineCreationServicesPlugin
Registry Setting: Set the REG_DWORD “Active” to “0”

b. Update the Catalog to the above MasterImage

2. For “Static” VDAs –

a. Push the registry key to the VDAs through GPO:

Registry Location: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\VirtualDesktopAgent\Plugins\MachineCreationServicesPlugin
Registry Setting: Set the REG_DWORD “Active” to “0”

b. Reboot the VDAs

Problem Cause

Citrix investigation has found that the changes introduced in VDA version 2303 and 2305 to the CommandQueue’s registration event handling mechanism cause a delay in the registration notifications from getting sent to the listeners, including the LaunchManager. LaunchManager waits for the registration notification to process the launch request, but due to the delay in receiving the notification, VDA is deemed as not registered and the launch fails. In addition, this would cause a re-registration of the VDA, following the failed launch. The above-mentioned workaround will address the issues a fix will be included in a future release.