All of the issues that we know of that could result in this behaviour should have been fixed by the 6.3 update.
However, this might not solve your issue: as detailed above, the 'summarising' screen would most commonly show up when the target application exited before providing any profiling data. This most commonly happens with profiling sessions that target Internet Explorer in some way (Silverlight, XBAP or ASP.NET sessions), generally due to the security settings in IE causing the profiler to be kicked out of the session.
Newer versions of the profiler will display the proper 'no results' message in these cases. Generally, switching off protected mode in IE is all that's needed to work around the problems (quitting any other open instances can sometimes be required as well).
I'm not aware of any issues that specifically hit WPF applications that could result in this. One trick you can try with desktop applications is to profile cmd.exe and then launch the applications you want to profile from there: ANTS won't end the session until the command window is closed.
Red Gate Software Ltd.