Vet inte om det här är riktigt ditt problem men det verkar vara något liknande.
Informationen är från september i år och går ut på att man ska ladda ner garmin Express och ansluta navigatorn.
Cause
This problem occurs because Garmin devices formatted with FAT12, FAT16, or FAT32 file systems aren't recognized as mass storage devices by a computer or device that's running Windows 10.
Resolution
To resolve the issue, download and install the latest version of Garmin Express software. The Garmin Express tool recognizes the connected device and updates its boot code to make it compatible with Windows 10.
Fixes an issue that prevents Garmin wearable devices from working after you've upgraded your computer or device to Windows 10.
docs.microsoft.com