Microsoft recently (April 29th) updated the free Windows Phone Developer Tools to line them up with the release version of Visual Studio 2010. If you have the original version released during MIX ‘10 (March 19th) you must remove it first.
Removing “Microsoft Windows Phone Developer Tools CTP” is supposed to clean everything up, but when I uninstalled:
the uninstaller failed to install “Silverlight 4 Tools for Visual Studio 2010 RC”.
I noticed “Microsoft Silverlight 4” and “Microsoft Silverlight 4 SDK” were installed more recently than March 19th. Removing that pair got me back on the uninstall path (well, the uninstall was then able to (re)install “Silverlight 4 Tools for Visual Studio 2010 RC”, then uninstalling one more time worked.)
Finally the coup de grâce, the April 2010 Refresh install (download.microsoft.com). If you missed an uninstall, it’ll tell you. I found there were a couple additional things I had to manually uninstall. Both Silverlight 4 packages previously removed will be reinstalled.
Here’s hoping the next update to the Windows Phone app development tools is simpler!