Well, I just tried it again and it didn't work. Emailed Garmin and got this response.
Thank you for contacting Garmin International.
I am happy to assist you. The Garmin is not compatible with Microsoft Streets and Trips. You can use the Garmin program BaseCamp for all of your routing needs the link below will take you this program. I am sorry for any inconvenience. Please let me know if you have any further questions.
BaseCampô | Garmin | United States
So, am in process of downloading BaseCamp. We'll see how that works.
Kinda crazy for it to work once, but now it's not compatible.