content: My six months old 4990 has a noticeable film deposits under the glass. The glass was clear when I bought it. Apparently other owners of the 4990 have had identicle problems (discussions at howtofixcomputers.com). Epson will clean it for free if the 4990 is still under warranty, but this is not a one time problem, but a continuous one (you have to pay Epson to clean the glass after warranty expires). The film is visible when the 4990 is powered up and the interior light is on. With the lid out of the way, look at the glass at 10 to 30 degrees angle. I hope your glass is clear.