My experience (Win7 / XP / OSX) is that the Octatrack needs to be plugged in whilst off to be recognised. Just plugging in and going to USB Disk mode, the driver never gets recognised.[/quote]
With my laptop (Win 7) if it is plugged in to USB audio and turned on when I boot the computer, the OT freezes.[/quote]
That sounds like an issue with your OS (Win 7) and the driver organisation. You should be able to work around that via Control Panel → Computer Management and force drive letter for the Octatrack.

You using any virtual drives, VMWare, MagicDisc etc?