According to Microsoft themselves, the Desktop Window Manager is always ON, there is a post lower down in that article that may be helpful in turning off the DWM but it may cause problems.

[url=http://msdn.microsoft.com/en-us/library/windows/desktop/hh848042(v=vs.85).aspx]http://msdn.microsoft.com/en-us/library/windows/desktop/hh848042(v=vs.85).aspx[/url]

Please send all technical issues, including the one you're describing, to Support. The more info we get from systems that are affected , the better the chance we ca work towards a solution. Thanks :)