Blend crashes when you open a Windows Presentation Foundation (WPF) application that was upgraded to a Microsoft .NET Framework 4.5.1-based version in Visual Studio 2013 Preview.
You cannot open a Silverlight 4.0 project in Blend after the project was ungraded in Visual Studio 2013 Preview.
You can now use Microsoft Test Manager 2012 together with Test Controller 2013 to create lab environments.
In an environment that has Microsoft Test Manager 2012 and Test Controller 2013 deployed, when you repair a lab environment that is in the Not Ready state, the test agent on the agent server is uninstalled unexpectedly.
You receive an error message when Visual Studio 2012 loads an F# project that was created by using Visual Studio 2013 Preview.
Team Foundation Server
Compatibility support is provided for discussion threads between Visual Studio 2012 and Visual Studio 2013 Preview.