Yesterday Lightroom 6 started choosing 2 photos for me in the Grid view, making it impossible for me to review all photos in a file unless I choose ALL the photos and then I can scroll through with the mouse or arrow keys. If I unselect all photos, it then chooses 2 photos for me, typically starting with the first two in the file in the upper right. If I unselect those photos and click on a photo anywhere else it will choose a second photo and then I can only scroll through those two photos (unless I choose more using CMD/click. I am running the latest version of Lightroom CC and Mac Yosemite 10.10.4 (latest version). I guess some file is corrupted but praying to google and searching here hasn't given me an answer. Any thoughts?
Anything special about your mouse, touch pad, Wacom pad, etc?
It's probably the touch pad on your Mac notebook that is causing the problem.