Citrix XenApp 6 Bug : Black screen during logon

Chris Hahn sent over this quick warning message for users of XenApp 6.  A potential bug with 11.x and 12.x windows clients accessing a Citrix XenApp 6 server.

When logging, there is no logon progress dialog for Published Applications until the login process completes.  For Published Desktops, there is just a black screen.  More information in depth conversation on this topic can be found on the Citrix Forums.

Unfortunately according to Citrix, to fix this, both a new client (12.1), and server side patch is required which have not been released yet.^{*
*(As of 09/2010)}