KB 2670838 make beginner suprise!

My project works fine and use pix for them many time without crash.One day, I start my project with debuger, when i exit my program the debuger said some thing wrong and interrupt at ‘Heapfree’.Also, I can’t pix my program. What’s going wrong?Check your pc whether instanlled ‘KB 2670838’.

How to fix?

solution 1.instanll windows8 SDK.

solution 2.uninstanll ‘KB 2670838’.

The reason is this update break the debug layer of dx.