I am using the Win8 Store Sample UI transcode app under Windows 8.1. The application is a fresh build after a fresh install of the Media SDK 2013 R2.
Using Visual Studio 2012 to debug the app I get the exception : Platform:COMException ^ at memory location 0x0035F6EC. HRESULT: 0x80040150. This value is defined as "unable to read the registry". I am running the app from VS as admin.
I was able to build this application and run it fine on this system a month ago with the same drivers that I am currently using. Attached is my system config.
I tried building and executing the 2013 R2 unmodified "Win8 Store Sample UI" sample and I do not see any issues. The sample builds and runs fine using Win8.1 and VS2012. I cannot see any apparent issues.
Please make sure you have all the recent Visual Studio 2012 updates, OS updates, developer license for Win8 UI development.
If you have specific details to share to help identify the issue please provide them directly via email.