If you are still on the Visual Studio 2010 RC1 build and Expression Blend 4 Beta in order to continue to develop for Windows Phone, Microsoft released updated tools that are compatible with Visual Studio 2010 RTM and Expression Blend 4 RC. First, read this link posted by Charlie Kindel that highlights changes, updates, and installation tips:
There are some nice fixes and improvements in this tools refresh detailed at the above link so open the link in another Internet Explorer tab and keep reading below to get going.
First uninstall the following:
Next install the following software to get on the latest version available of the Windows Phone Developer Tools:
1. Install Visual Studio 2010 RTM from MSDN Subscriber Downloads (Not required unless you want the full Visual Studio 2010 development experience:-))
I also installed the Silverlight 4 Tools RC2 located here since I work in Silverlight quite a bit.
2. Install Windows Phone Developer Tools CTP – April Refresh
Details of what’s new/changed: http://windowsteamblog.com/blogs/wpdev/archive/2010/04/29/windows-phone-developer-tools-ctp-refresh.aspx
3. Install Microsoft Expression Blend® 4 Release Candidate (RC)
Note: If you already have Expression Blend 4 RC, you should uninstall and reinstall. This post has more info.
4. Install Expression Blend Add-in Preview 2 for Windows Phone
5. Install Expression Blend Software Development Kit (SDK) Preview 2 for Windows Phone
Here is a link to the updated Docs for the April tools CTP refresh: