The last windows update --> really screwed with FTDI drivers and ports (windows 10 and 11). The fix is: 0 - Download the files listed below. 1 - Unplug all usb devices 2 - Reboot your PC 3 -Run --> CDMUninstaller.exe as Admin and perform the following steps Clear the Product ID Click Add Click Remove Devices Close the program 4 - Reboot the PC -- verify that no USB devices are connected 5 --> Run -->CDM212364_Setup.exe as Admin with NO USB devices connected 6 -- Connect your Device back to the PC. 7 --> Most likely the COM port number changed due to the windows issue --> use device manager to see what com port is active when your product is connected. 8 --> Start your software and adjust the COM port to use the correct port.