Never be a problem before update . My watch already connect to laptop ,but once you press sync
Garmin express can't find the device ( Garmin Express 7.17.0 )
I find out Express 7.17.0 is a problem , I reinstall 7.16.1 from Time Machine , both watch / Mac sync now.
I have the same issue since 15.9 was installed. I tried all steps and they failed. I have a 955solar and I use a Mac for Garmin Connect.
Remove and add the device again to Garmin Express