Open CPN and a Garmin 72H

[mestrezat]

I've got a new Garmin 72H for a GPS for my Open CPN program. When I plug it into my computer, it freezes the program. Locks it solid so no keys work at all. I unplug and kill the program and when rebooted it works fine as long as I don't have the 72H plugged in.
I contacted Garmin and they told me to download and install new drivers. Did so with no difference. Still locks up the program. If I use the input from my AIS transponder, the GPS feature works fine so it's not the program. I got into the program and activated the Garmin feature in the tool box under communications so the program knows it's there.
Any suggestion where I'm going wrong.

[S/V Alchemy]

I will be watching this as I have a Garmin 72H myself. I haven't used it with OpenCPN, however: I use a BU 393 (?) USB 'puck' and just fiddled with the baud rates until it worked, which it does.

I use the Garmin unit as a standalone lat/lon as it's pretty fast at acquisition.