Chromium Embedded Framework won't build or run
I assume you are referring to either the cef_simple or the cef_client projects that come bundled with the libraries...
Fix
Set the macro value for CEF_ENABLE_SANDBOX to 0 in cef_simple.cpp and cefclient_win.cpp
What's happening
The error indicates that a library you are linking to is not compatible with simple_app.obj. In this case, this library (cef_sandbox.lib) is built with _MSC_VER 1800 (that's VS2013 beta, if I am not wrong) while your current environment is _MSC_VER 1600 (VS2010).
Had the same problem a couple days back - cheers!