MobileMate with 128 gb San Disk Extreme micro SD card not recognized on one Windows 10 Pc. but is recognized on another. If I use a USB Hub, the MobileMate with SD card is recognized on first PC. Any suggestions what the problem could be?
This sounds more like a USB power, port, or driver compatibility issue on the first Windows 10 PC than a problem with the SanDisk card. Since the MobileMate works through a USB hub, try another USB port, update/reinstall the USB and card-reader drivers, and disable USB power-saving in Device Manager.