One day I’ve decided to install WinFX (along with VS 2005 beta 2) on my laptop to see how it works on hardware accelerated graphics (I take a look at WinFX before – in VMWare Workstation though). So I installed everything as requested. The first step to test it was to run XAML Pad, a utility to build UI using XAML. No go. I took a look at Fusion Log Viewer (fuslogvw) I saw that XamlPad application tried (unsuccessfully) to load totaly unrelated 3rd party assemblies built for .net 1.x (plus some of .net 1.0 system assemblies). Go figure. I haven’t put much effort into solving this (who has time to play these days). I’ve rather posted a reply to a guy having same problem in MS newsgroup microsoft.public.windows.developer.winfx.avalon (“XamlPad.exe NullReferencException with WinFX CTP Sept.” thread).
After a while, Daniel Danilin found (in another post in same thread) an (obvious) solution: remove offending 3rd party (not .net 1.x system ones) assemblies from GAC. While this solution isn’t perfect (what about applications that use those assemblies?) it just works – and I have something to play with while traveling to my second MVP summit.