http://developers.de/blogs/damir_dobric/archive/2013/08/06/windows-store-apps-combobox-catastrophic-failure.aspxIf you read this post, you are probably frustrated and have been redirected by some search machine:) The error you have sounds like: Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED)) If you are running in debugger, you will evenenCommunityServer 2008 SP1 (Build: 30619.63)