This is a great post from Citrix; post can be found here: http://forums.citrix.com/thread.jspa?threadID=282924
Based Citrix Technical Support experience and customer feedback, the following Citrix and Microsoft hotfixes have been found to resolve the most common issues with XenApp 6 and Windows Server 2008 R2. These hotfixes focus on basic functionality and stability. For a complete list of Citrix hotfixes for XenApp 6, please click here.
- Installing hotfixes or performing a repair on the base product for Citrix XenApp 6 for Windows Server 2008 R2 can inadvertently remove the Citrix Licensing component, if present, from the system. This fix prevents the Citrix Licensing component from being removed when installing subsequent hotfixes. Replaced by XA600W2K8R2X64060
- Servers running XenApp 6 can become unresponsive while shutting down. The issue occurs when when the picadm.sys driver encounters certain error conditions that prevent it from shutting down gracefully. Replaced by XA600W2K8R2X64046
- This enhancement is a part of the XenApp Printing Optimization Pack. The Printing Optimization Pack improves the user experience and printing speed by reducing the printer bandwidth required. For more information, including system requirements, required components, and known issues, see XenApp Printing Optimization Pack in eDocs, the Citrix Product Documentation Library.
- This fix addresses session reliability issues that can occur when using multiple, disparate client devices to reconnect to the same session.
- Certain applications fail to launch when Admin Approval Mode is enabled in User Account Control. Replaced by XA600W2K8R2X64068
- This fix addresses a security vulnerability. For more information, see Knowledge Center article CTX128169
- Attempts to log on to a XenApp 6 server using Version 7 or earlier of the clients can cause svchost.exe to exit unexpectedly. As a result, further connection attempts to the server fail until it is restarted.
- The CPU consumption of the CitrixCseEngine.exe process can spike unexpectedly and cause logon delays.
- Attempts to launch a published application that resides on a mapped network drive rather than on a XenApp server fail
- Servers might experience a fatal exception, displaying a blue screen, with bugcheck code 0xf4 on IMAAdvanceSrv.exe.
- Attempts to launch Windows Internet Explorer from an http, https, or mms hyperlink embedded in a streamed application fail. The issue occurs because XenApp 6 does not create the HKEY_CLASSES_ROOT\htmlfile\shell\opennew\command_backup registry key as part of server file type association
Added – 8/9/2011
- Servers might experience a fatal exception, displaying a blue screen, while shadowing is started.
- Considered a Critical Update from Citrix: This fix addresses a security vulnerability. For more information, see Knowledge Center article CTX129430.
- Servers might experience a fatal exception, displaying a blue screen, on picadm.sys. The issue occurs when the user removes a thumb drive from a client device while connected to a session.
- Servers can experience a fatal exception, displaying a blue screen, on picadm.sys. Dumps indicate that picadm.sys is referencing invalid, possibly disconnected volumes.
- When the ReadOnlyMappedDrive registry key (HKEY_LOCAL_MACHINE\SYSTEM\Current Control Set\services\picadm\Parameters) is set to 1, published applications can no longer access and browse mapped client drives.
- With folder redirection enabled, servers can experience a fatal exception, displaying a blue screen, on picadm.sys. The issue can be observed when attempting to save a file that was introduced into the session on a USB device attached to and then removed from a thin client device.
- Servers with Hotfix XA600W2K8R2X64018 installed can become unresponsive intermittently. The issue occurs when a scheduled reboot is triggered by a Citrix policy while there are active sessions on the server.
- Unplugging a USB device from a thin client while a file is being copied to or from the USB device, can cause the following error message to appear:”An error has occurred. The destination you have specified does not exist. It might be an offline network location or an empty CD or DVD drive. Check the location and try again.”After clicking Cancel in response to the error message, the session eventually becomes unresponsive
- Child windows of some applications position to where their lower boundaries dip below the Windows Taskbar. This is the server-side component of the fix. To resolve the issue in its entirety, you must also install a client-side hotfix that contains Fix #206851.
- Dock bars of published applications might overlap and obscure the local Windows Taskbar. This is the server-side component of the fix. To resolve the issue in its entirety, you must also install a client-side hotfix that contains Fix #206851.
- When run in seamless mode and/or in multiple monitor configurations, certain applications experience screen flickering.
- Certain applications can perform slowly when run in seamless mode.
- The CPU consumption of the winlogon.exe process can be higher than usual and cause new connection attempts to fail once a server hosts 70 connections or more. Eventually, servers can experience a fatal exception and need to be restarted.
- This fix addresses two installation issues:
- Hotfixes fail to install on a XA6 server that has not yet had the XenApp Server Role configured.
- Installing hotfixes or performing a repair on the base product for Citrix XenApp 6 for Windows Server 2008 R2 can inadvertently remove the Citrix Licensing component, if present, from the system. This fix prevents the Citrix Licensing component from being removed when installing subsequent hotfixes.
- A Windows Server 2008 R2-based Remote Desktop server denies some connection requests randomly under heavy logon or logoff conditions
- Delay when you shut down, restart, or log off on a Windows Server 2008 R2
- Stop error in Windows 7 and in Windows Server 2008 R2 if a heavy load situation exists or if connectivity issues exist: “STOP: 0x000000B8″
- A computer that is running Windows Server 2008 R2 stops responding randomly
- An application or service that uses Winsock API or Winsock Kernel API may randomly stop responding in Windows Server 2008 R2
- Installs 32-Bit help System 2008R2 may be required if hosting 32-bit applicaitons
- Remote desktop sessions do not completely exit, and you cannot establish new remote desktop sessions to a computer that is running Windows Server 2008 R2
- Startup takes a long time on a Windows 7 or Windows Server 2008 R2-based computer that has an Intel Nehalem-EX CPU installed