Hello. Like the question above I purchased a used Maschine MK I. When I try to enter a serial number for the software it requires 25 digits. I do not see it anywhere on the original box or on the underside of the hardware. Any idea how to go about retrieving the serial number? Or am I out of luck with getting the software? I can return it within 10 days so if its a no go then that's what I'll do. Thank you in advance for any help.