Broker or Virtual Delivery Agent (VDA) sessions do not log off automatically after the user closes all the hosted applications. This results in some sessions being active on the VDA machine. After the server has reached its threshold, further logon requests might be unsuccessful.

Requirements

Administrator privileges to perform this operation. This operation should be performed on the master image that is used to build the VDA machines.

Workaround

Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.

Complete the following steps as a workaround to fix this issue:

1. Login to VDA Base image as an Administrator.

2. Open Windows Registry Editor using RegEdit.exe.

3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Citrix\wfshell\TWI.

4. If this path does not exist, create the path.

5. Check for REG_SZ value named LogoffCheckSysModules. If this value does not exist, create the value.

6. Add the following entry to LogoffCheckSysModules.

   Type of VDA	String to be added to LogoffCheckSysModules
   RDS (for example, Server 2008, Server 2012)	AppVStreamingUX.exe,AppVShNotify.exe
   Workstation (Windows 7, Windows 8)	AppVStreamingUX.exe,AppVShNotify.exe,PicaUseragent.exe

Problem Cause

In XenDesktop 7.0, Citrix supports App-V 5.0 applications in a VDA session.

Usually, once all the applications in a VDA session are closed, that session is automatically logged off.

App-V 5.0 service, running on VDA, starts two processes in the context of starting user AppVStreamingUX.exe and AppVShNotify.exe. These processes sometimes do not end even after closing all the App-V applications in that session.

VDA session is not auto-logged off after the user closes all the hosted applications because of these background App-V processes. This can result in sessions that do not log off. Further logon requests are also denied.