user type detection is an important part of how the firewall deals with maliciose users, the decission of preventing a assignment should be well thought over.
Look at the rules that where triggered that caused the evaluation
Requirements
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2