I have just used Garmin Express to install the latst TopoActive EU 2021.10 map. The installation was completed normally and Express confirmed that I had the latest update. I ejected the device, then booted it up - the TopoActive maps were both installed okay and render normally on the screen.
However when I plug the 66st into my Win 10 PC, the device is not mounted and can't be accessed by File Explorer.
I have tried to fix this - I have installed latest USB drivers and tried the Forced USB Mass Storage Mode steps several times without success. I have tried two Garmin cables and different USB ports. What else should I try?