Graeme, > Run it with -D5 and capture the output, and send it to me. Here it is: C:\Users\Roger\Desktop\dispcalGUI\Argyll_V1.0.3\bin>spotread -v -D5 usb_get_paths about to look through buses: usb_get_paths about to look through devices: usb_check_and_add() called with VID 0x971, PID 0x2003 usb_check_and_add() found known instrument icoms: There don't appear to be any serial ports Connecting to the instrument .. i1disp: About to init coms i1disp: About to init USB icoms: About to set usb port characteristics icoms: About to open the USB port icoms: USB port needs opening icoms: About to open USB port 'usb:/bus0/dev1 (GretagMacbeth i1 Display)' icoms: USB port is now open icoms: Clearing any USB errors icoms: usb port characteristics set ok i1disp: Sending cmd 00 args '' response '4c 4f 43 4b 00' ICOM err 0x0 i1disp: init coms has suceeded i1disp: About to init instrument i1disp: about to check response and unlock instrument if needed i1disp: Sending cmd 00 args '4c 4f 43 4b 00' response '4c 4f 43 4b 00' ICOM err 0x0 i1disp: Sending cmd 0e args '47 72 4d 62' response '00' ICOM err 0x0 i1disp: Sending cmd 00 args '00' response '4c 4f 43 4b 00' ICOM err 0x0 i1disp: Sending cmd 0e args '4c 69 74 65' response '00' ICOM err 0x0 i1disp: Sending cmd 00 args '00' response '4c 4f 43 4b 00' ICOM err 0x0 Instrument initialisation failed with 'Not expected instrument model' (Instrument status is unrecognised format)! icoms: delete called icoms: closing port usb_close_port() called usb port has been released and closed