Under certain circumstances, your Edge device may either fail to power on to the main menu screen, or may not be recognized when connected to a computer. If this occurs, the device can be forced into mass storage mode, allowing it to be seen by the computer and Garmin applications.

Before proceeding, ensure you have covered the basics here: My Garmin Fitness Device is not Detected by Garmin Express

To force an Edge into mass storage mode:

Disconnect device from computer
Power device off
Press and hold appropriate button(s)

Edge 20 and 25: START/STOP (top-right button)
Edge 130: START/STOP
Edge 200: PAGE/MENU (bottom-left button)
Edge 500: Hold POWER/LIGHT and PAGE/MENU simultaneously
Edge 510, 520,520 Plus, 530, 800, 810, 820, 830, 1000, 1030: LAP/RESET
Edge 605 and 705: Hold Thumb Stick in up position
Edge Explore, Explore 820, and Explore 1000: LAP/RESET
Edge Touring/ Plus: LAP/RESET

Plug device into computer
Wait until device is recognized by computer (may take up to 30 seconds)
If prompted, install USB device drivers:

Choose, "No, not at this time"
Click Next
Choose Install USB drivers automatically (Recommended)
Click Next and wait for USB driver installation to complete
Click Finish

Release appropriate button(s)
Sync history and update device firmware if not up to date using Garmin Express
Right-click on device drive
Click Eject
Disconnect device from computer
Power on device (wait for firmware update to complete if installed)

If you continue to have an issue with your device being recognized please contact Product Support.