Symptoms

When Installing the Virtual Desktop Agent in XenDesktop 4.0 environment on a Windows 7 64-bit Edition, the following error message appears:

"The version of Citrix Virtual Desktop Agent x64 is not compatible with Windows Display Driver Model (WDDM) display drivers."

 

 

Cause

 The Physical Vista machine most likely has a WDDM graphics driver installed for the display adapter installed in it. The current version of the Thinwire Graphics driver used by ICA is an XPDM driver. In Windows Vista (and 7), the Windows operating system itself automatically disables XPDM drivers (including the Citrix Thinwire driver) if a WDDM display driver is present on the system.

Workaround

To work around this, you must uninstall the WDDM Display Drivers for the physical machine you want to install a VDA onto. You also must prevent Windows update from re-installing these drivers to prevent Thinwire being automatically disabled again by Windows.

If you want to install XenDesktop VDA on a Windows 7 or Windows Vista physical machine with WDDM driver already installed, use the following steps:

解决方法：

Open a command prompt and Go to the location where xdsAgent.msi is kept and use following command:

msiexec /I xdsAgent.msi INSTALLONWDDM=1

http://support.citrix.com/article/CTX123529