As I already posted in this thead, D3D11 and DXGI seems to be causing some strange warnings and exceptions in the debug output on Win7 x64.

Does anyone know why this is happening and how/when it will be fixed, or if it's harmless?

Basically during the SetFullscreenState call the debug output gets flooded with _com_error's and after that it shows the DXGI warning about Fullscreen Presentation inefficiencies, which is afaik only supposed to happen when DX is unable to flip the backbuffer and has to BitBlt.