Hi there!
Using Garmin Express 5.9.0.0 and Windows 10 with all the updates applied. Garmin Express has no problems finding my 920XT, syncing and updating it etc . Have now bought Garmin's USB Ant stick and Bike Cadence sensor. Tried to add them to Garmin Express but only got the message "We found an ant stick but didn't find a device". The Ant stick is visible among the other Windows devices and when I went to Zwift it immediately connected to my trainer, the Heart Rate Monitor that came with the 920XT and the new Cadence sensors, everything via Ant.
Obviously something with GE that doesn't work well!?