Can't add folder to library, but can add the same files to library individually.

Hey everyone,

I'm trying to add a large folder with lots of subfolders that have music in them, but when I use File > Add Folder to Library... and select the top folder, not all of the music is imported. On inspection, it looks like some of the subfolders in the directory simply aren't being read. Individually selecting an offending subfolder and using Add Folder to Library still doesn't work. I can use File > Add File to Library... then browse to the subdirectory and select the actual files, and they are successfully added to my library.

Normally this would be fine, but I am adding a large directory with a subfolder for each artist, and roughly a third are exhibiting this problem. To figure out exactly which are missing and individually browse to each artist folder to add the files would be a huge waste of time. I haven't seen a pattern or clue to why those subfolders are failing, but I've tried importing the whole thing multiple times and it seems to be the same subfolders each time.

Anyone have an idea why iTunes wouldn't recognize that a folder contains music files when using Add Folder to Library, even when I know it can accept those files by adding individualy?