I have Visual Studio 2010 Ultimate and I have just upgraded my ESRI software (ArcReader, Engine, Desktop, Server, License Manager, and ArcObjects SDK for MS .Net to version 10.1. I have multiple VS projects that were working under ESRI version 10. But now when I open the forms in design mode, if the form has an ESRI control on it, Visual Studio crashes. By crash I mean that the IDE disappears and the devenv.exe process continues to run but becomes completely inaccessable. I can build these projects and produce new executables that work under 10.1 (yes, I changed all of my file references). I have tried following the "Building a map viewing application using the ArcGIS Engine controls" walkthrough and as soon as I drop the license control on the form, VS crashes.
I suspect that there is some problem that happened during installation, but it looks like everything is fine, I can see the templates for ArcGIS Desktop Add-Ins, Extending ArcObjects and Server Object Extensions. The Framework is set to 3.5, and I have tried 4.0. I've checked my licensing and I have the ArcGIS Engine Developer Kit Version 10.1 product installed and Authorized.
Any ideas about what else could be going wrong here?