Why you shouldn't enable RDP via GPO on XenApp/RDS Hosts

I recently had to troubleshoot a Problem where the Customer told me that sometimes all the Sessions on a XenApp 6 Host got disconnected and the Users then had to reconnect to their XenApp Sessions to continue working.

After a little Research (more like googeling) I narrowed it down to the the Group Policy Refresh. Not always, but sometimes, when doing an "gpupdate /force" all User Sessions on the XenApp Host got disconnected. With this in mind I found the following Microsoft Knowledgebase Article: http://support.microsoft.com/kb/2083411

The customer in fact used the Group Policy Option "Allow users to connect remotely using Terminal Services" to enable Remote Desktop and force a specific Remote Desktop Security Setting on all of his XenApp Servers.

After setting the Registry Key "fDenyTSConnection" to 0 (as suggested in the Microsoft KB Article) the sudden disconnects were gone.

Problem solved! :)

PVS and vSphere 5 PXE Reboot Problem

I recently worked in a Project where we deployed XenApp 6.5 Workers via Citrix Provisioning Services 6.0 (PVS) onto a vSphere 5 Cluster and ran into a Problem regarding the PXE Boot. We knew that PVS 6.0 is currently not supported with vSphere 5, but the customer wanted to use his vSphere 5 Cluster nonetheless.

Everytime we rebooted a Target Device, running an XenApp 6.5 Worker, it would reboot and then hang on the PXE Boot like this:

When we powered the VM completely off and then started the VM again (cold reboot) the PXE Boot worked without a Problem. The Problem would only occur when rebooting the VM without completely shutting it down before.

To fix the Problem we had to enabled the "Interrupt safe mode" Option in the Bootsptrap Configuration of the Provisioning Servers:

And voilà: Rebooting the XenApp 6.5 Workers on a vSphere 5 Host/Cluster now works as expected.

UPDATE: Citrix published an official Support Article (with the same Solution) regarding the Bootstrap Configuration in an vSphere 5 Enviroment: http://support.citrix.com/article/CTX131993

Citrix XenApp 6/6.5 and the Error: Event 602, PrintService

I recently had a customer where on all XenApp 6 Workers an Error with the EventID 602 from the Source PrintService was logged in the EventViewer during the User Logon Process. This only seemed to happen when using Session-based Printers in the XenApp Session.

After a bit of Research I found a Microsoft KnowledgeBase Article with an Hotfix which fixed the Problem: http://support.microsoft.com/kb/2457866

Note: This Hotfix is NOT included in the Windows Server 2008 R2 Service Pack 1. I have only tested this on XenApp 6, but this should also apply to XenApp 6.5 Systems.