Problem solved with your message in post =
* If using a daisy chain setup, disconnect the second monitor. Only have a single U2518D connected to the computer which is installing the firmware update
* Connect the U2518D to the computer via the USB upstream cable and one video cable so that you can still see the Windows desktop
* Disconnect all USB peripherals (mouse, keyboard, HDD) from the U2518D side and bottom USB downstream ports
* Those USB peripherals (mouse, keyboard) should be plugged directly into the computer
* Disable any antivirus software
* Reset the U2518D to Factory Default settings in the OSD (On Screen Display) -Others
* Download/save the U2518D firmware update to the Windows desktop
* Run it and it will ask "where to unzip"
* Click the yellow folder on the right
* Click Desktop
* Click OK
* You will see, "C:\Users\user\Desktop"
* Add \FW to the end of that line, "C:\Users\user\Desktop\FW"
* Click OK
* Open the FW folder on the Windows desktop
* Open the Firmware Update Instruction.pdf
* Review this PDF before running "MonitorFirmwareUpdateUtility.exe"