Movies no longer in directory

All of a sudden about half of my movies from my external are not showing in the directory. 

They were showing this morning,   they are still showing ON the drive when I search it through the network.  But they are no longer in my icon menu.

Suggestions?

Does that occasionally.  Clear your media library.  Go to Setup  -->System —> Media Library —>Clear Media Library.

Let it rescan your files (can take up to an hour depending on how many files to scan, usually much shorter).  After that all should be well.