Does iTunes have a limit on the number of movies it can list? I have a very annoying problem. Using HandBrake I have been able to rip and hereafter metatag all the family's 1500 movies for our iTunes library.
Once, I couldn't find the movie I was looking for, even though I knew it was tagged and stored. I also knew that it has been watched before through the Apple TV.

I went to our iTunes Application and saw that only 814 movies were shown. (That's what it said in the bottom) I got afraid that all my movies were gone, but after looking in the files folder, I realized that all movies actually still existed. I tried to import some of the movies again and iTunes actually showed them, but then some of the existing movies disappeared. Still only 814 movies.

My question is: Does iTunes have a limit for the amount of movies able to list in the application? I know it can't be about RAM and HDD since there is about 1,5 TB HDD left and the computer has 16 GB RAM.. 

I also tried to update the iTunes version, but it didn't seem to work.. Any suggestions?

EDIT:

Just to inform you.. I am able to continue importing music and tv-shows without problems.
Be careful about creating a new library - make sure you have a backup first of the Library files first!

I've "lost" things in iTunes too.  Try creating a new playlist, and drag one of the missing movie files from the Finder right into the new playlist.  Even if it's already in iTunes, this will add it to the playlist.  If it's not in iTunes, this will add it to the Library and the playlist.

If it shows up in the playlist, but it's still not in the Movies section, check the "Media Kind" value on the Get Info -> Options tab.  Make sure it's set to "Movie", not "Home Video" or something else.

If it can't be added to the playlist at all (and really isn't somewhere else in iTunes already), it's probably in a format that iTunes doesn't support.  I know you said most of the HB-encoded movies are there, but that doesn't mean that some of them aren't somehow encoded (or maybe tagged) differently, and iTunes is choking on that.  Check the encoding settings carefully in QuickTime and VLC, and the tags in MetaX or the equivalent.