XenDesktop Logon Failure: Desktop Viewer Pops up and Closes

Know this problem? You try to start a XenDesktop session, Desktop Viewer opens … and closes. Then nothing.
When you look at the machine in Desktop Studio you find that everything looks good: it is registered with the DDC and it is not in maintenance mode. However, you find an event with the following properties in the application event log:
Citrix/Terminal Services/Remote Desktop Services












