MacDive Forums

This is the error message:
Failed connecting to dive computer on serial port '/dev/tty.usbserial-20030001' (Error Code: -4)

That serial port is usually for Oceanic devices. Do you have another dive computer you have used previously with MacDive?

Perhaps you selected that port, which means MacDive won't try and guess the correct one. Plug in your D9tx and then Preferences -> Advanced -> Scan For Serial Port.

And ideally, you leave that field in preferences blank so that MacDive *will* try and guess, which means both your devices will download without having to do this every time.