Check whether this is obstructed or if the sensor is loose on the circuit board. Sometimes a plate is used between sensor and disk/scroll wheel so that each sensor gives either a high or low state when th second sensor transitions. My mouse seemed to have one sensor for the scroll wheel, but there may be two active elements built into the casing of the sensor. If a controller is plugged in at the same time as your mouse, unplug it. Make sure there’s no dirt blocking your scroll wheel. If you’re using a wireless mouse, check or change your batteries. For roller ball mice, two sensors are used for each of the encoding disks for x and y movement of the roll ball. Why does my computer keep scrolling by itself Check for Issue with your Mouse Plug your mouse into a different USB port. I'm not quite sure how roll direction is worked out for the scroll wheel. Is the mouse a roller ball or optical type?Ĭleaning the rollers and roller ball with meths or IPA removes any grease/fluff which can prevent the rollers from turning. My mouse problem is very different, i have 4 different mouses, all of them work, all of them new but my pc wont detect the scrollerĮugene Brennan (author) from Ireland on January 12, 2017: These setting layout may be slightly different depending on your operating system and mouse type. Under the scrolling tab, check whether scrolling is enabled.

Launch Control Panel, go to mouse settings, then the buttons tab and check whether 'connected device' corresponds to your device.

Mouse keeps scrolling down