Dirty platen The glass platen has a film on the underside where I cannot clean unless I disassemble the scanner and that looks problematic.  If there is an easy way to get at the other side I would like to know.  Otherwise a professional clean costing about as much as a new one most likely.

I just did it! (After reading the answers here in despair.) After taking off the lid, I locked the transport (using the slider underneath the scanner near the front). I laid the scanner face down on a carpet. I undid the two small Philips screws at the back of the scanner, and eased two of the side lugs sideways using two small standard screwdrivers, to enable one side of the base to move up a little, then the other. Then the top came away easily (it hooks on at the front). There are no connections between the top, with the glass, and the base, with the mechanism. The buttons go with the top, their switches stay with the base. It needs a little bit of confidence with machinery, but not a great deal. Don't forget to unlock the transport afterwards.

I had the same issue. This is my second unit - I returned the first one when I noticed the problem. The new unit had the same issue out of the box. I disassembled it and cleaned the glass. The film reappeared almost immediately. Perhaps these units run hot and produce minute quantities of smoke (?). This problem does not seem to affect the scan quality as I scanned thousands of pics with it, many of which appeared in a book.
I used the scanner for four years and now it died. Was well worth the money.

I had the same issue. This is my second unit - I returned the first one when I noticed the problem. The new unit had the same issue out of the box. I disassembled it and cleaned the glass. The film reappeared almost immediately. Perhaps these units run hot and produce minute quantities of smoke (?). This problem does not seem to affect the scan quality as I scanned thousands of pics with it, many of which appeared in a book.
I used the scanner for four years and now it died. Was well worth the money.

My suggested solution was to become an Elite Expert and to consult myself.