I’m so annoyed that this isn’t documented anywhere. After two previous Clips, I bought the Sport. Nowhere in the documentation does it say that it can be locked. I accidentally figured out how to do it. Hold the BACK arrow down (the arrow at the top left of the controls), and it will lock! I gave this unit a 1 star on Amazon because of the lack of a LOCK feature. It seems I wasn’t the only one who was annoyed about not having one. I would have thought that SanDisk would have chimed in to let us know. Unlock, of course, by holding the same back arrow button down. Sheesh.