Just updated to 6.21 for W10 and STILL getting error to install 4.7.2 even though the 6.21 install completed with no errors and 4.7.2 has been installed successfully with no errors. I have restarted between each and every install, uninstall, reinstall multiple times.
I have not been able to use Garmin Express for MONTHS due to this error.
I am now looking at replacement watches that perhaps can provide proper tech support. It's a shame, as this has been most useful but it is worthless without a data transfer capability.
