Yesterday I was at a customer to troubleshoot the two newly added Citrix XenApp 6 servers to their existing farm. The existing farm worked without any problems but the two new Citrix servers wouldn’t accept sessions. If a session was started directly the logon process would stop at the ‘Welcome’ screen from the ICA client. I tried to troubleshoot this problem but the logfiles couldn’t point me in the right direction until I noticed that SP1 for Windows Server 2008 R2 was installed.
The Citrix farm runs on a VMware vSphere platform and the Windows hosts where created based on a template and the Citrix XenApp servers in the farm where based on a pre-SP1 image but the two new servers where based on a SP1 image. After installing CTX125388 (Hotfix XA600W2K8R2X64001 – For Citrix XenApp 6.0 for Windows Server 2008 R2 – English) the problems where solved.
So leasons learned: Install this hotfix after you deploy XenApp 6 on a Windows Server 2008 R2 SP1 machine and make sure you communicate these kind of changes, it prevents unnecessary problems.