Try connecting your modem directly to your computer to rule out router-related slowdowns.
Garmin Express requires a high-speed home connection like DSL or Cable. garmin express slow download
Firewalls and antivirus programs can mistakenly flag Garmin's heavy data traffic as a threat, slowing the process. Try disabling them temporarily or adding Garmin Express as an exception. Try connecting your modem directly to your computer
Garmin Express fails to complete the "Downloading files" stage garmin express slow download
Wireless interference can cause fluctuating speeds. If possible, plug your computer directly into the router with an Ethernet cable .