First check the CQXT Touchscreen calibration as described in more detail at https://support.hunterlab.com/hc/en-us/articles/206620506-How-to-calibrate-the-Touch-Screen-on-a-ColorQuest-XT
Power off the sensor, then power back on, as soon as the logo appears in the center of the screen, touch the logo.
This should bring you to the calibration screen where you will be asked to touch specific points around the perimeter and middle of the screen.
If you run this touchscreen calibration procedure and the screen still has dead spots then you may need to replace the Touchscreen Overlay. This is a film that covers the LCD screen and is connected to the processor board via a ribbon cable.
The part number for this is D02-1014-800. Contact HunterLab for pricing and installation instructions.
Alternatively you can request an SRO to have the sensor returned to the HunterLab Service for repair.
Edited by Charles and Gordon