EFILive now uses a special Microsoft ID string in the USB enumeration (so that it works carefree with Windows built in drivers) and for some reason that appears to be causing problems for Macs.
A couple of customers have run into this but apparently it still works on some older Macs (indicating the issue sits with the Apple hardware and / or Parallels).
Sorry to say but at this stage there is little EFILive can do to resolve this, we went to the updated drivers so it was easier for the 99% of customers who are using native Windows machines with EFILive.
