[Value data type] REG_DWORD [Description] If this policy value exists and is set to 1, the installer writes common debugging messages to the debugger using the OutputDebugString function. If this value exists and is set to 2, the installer writes all valid debugging messages to the debugger using the OutputDebugString function. This policy is for debugging purposes only and may not be supported in future versions of Windows Installer. [Policy] 
Debug