There is a bug in Windows XP that makes WinMLS select the wrong input line for the mixer. We have compensated for this, so it should work. This is a problem only for the sound cards that can select between line input and mic input in the WinMLS mixer (not e.g. the Digigram VXpocket). Note that the Windows XP bug may be fixed in future versions of the operative system. If so, see the Specific sound card settings section in the Measurement->Sound Card… referenced section for more information.