XenDesktop uses a different way to implement the DefaultPrnFlags registry setting. Unlike XenApp, where multiple sessions run on the server at the same time, VDAs in XenDesktop run only a single sessions at a time.

So, it doesn't store a farm-wide configuration in the DefaultPrnFlags key in each VDA agent. XenDesktop employs a different approach of using XML blob where both farm and policy wide information is passed to each Virtual Desktop Agent during the start of a session. The information is captured at the desktop Delivery Controller from various resources and then passed in the form of an XML document.

You can use the PortICASetDefaults tool to set the DefaultSessionFlags value in XenDesktop. When a logon is initiated, session settings for printing are collected from policies, Terminal Services defaults, and the DefaultSessionFlags value from the XML blob.

You can modify the system default values by the following procedure: