Thanks for your help Jeffrey.
When using a Windows 10 laptop using Instacal 6.72, it identifies it as a USB-TC. The detected S/N is 15D9D11.
On the problem system, I see the same problem whether using MCC 6.73 or 6.53. Using 6.53, by going to Device Manager -> DAS Component, it shows USB-2020 with a '?' sign on the icon. On the Properties -> Details tab the 'Driver Assembly Description' shows 'USB-2020'. If while on DAS Component->USB-2020 right click and 'Uninstall' the driver, and checking 'Delete the driver software for this device', the 'DAS Component' category disappears so no more 'USB-2020' device is present. Then if I reboot the PC, after reboot completes, a 'Device driver software was not successfully installed' message is shown even though the device is not plugged in. Also, Device Manager shows an 'Other devices' category where USB-2020 is shown. The icon for it shows an exclamation mark.
Please comment.