Mine suddenly lost the ability to scroll downward over the weekend, after just four months of not particularly heavy use. I happened to have a sealed unit at work (though not work-related—long story), and attached it here. Took about a minute to be recognized, and thereafter smooth functioning, which appears to let the software off the hook. Four months seems a rather short time for full functionality to be compromised—I'm curious to know whether the mouse is included in my one-year warranty.

cordially,