I was a bit disconcerted when I put in a DVD and thumbnails came up from a previous, different DVD I had played (Leopard 10.5.4, Player 5.0.1). What the....? This was nothing I told it to do--it just stored them. So, as there is apparently no "clear cache" button, the only answer seems to be: user > library > app support > DVD player > settings. I deleted all but the "Global" & "Shared" files. That worked for me. Didn't seem to disturb functions. Comments? (I am pretty new to Macs).