On a Windows computer with several ports (COM & USB) the following may occur:

When opening the measurement device configuration dialog and selecting the DTP70 connected to an USB port, it might be, that the DTP70 will not be found. Additionally a connection port like 'COM x' is pre-selected and grayed out and cannot be changed to the appropriate USB port or to the 'Auto' port.

If you have this situation, please select any other measurement device (wait until it is not found), then switch the connection port to 'Auto' and go back to the X-Rite DTP70.