I have noticed lately that some of my mp4 files do not show in iTunes even though they are in the iTunes directory. For instance I have 4 seasons of a popular ITV detective series and whilst seasons 3 & 4 show in iTunes seasons 1 & 2 do not. I have checked the info (using get info) of the files that show with the files that do not and every thing looks OK. I have consolidated the library to no avail and have imported them to iTunes on a different computer but the same thing happens. Seasons 3 & 4 show, seasons 1 & 2 do not. Is this because iTunes only opens in 64 bit mode now?