Hello Mac-Forums!

I happen to notice that some of my .mp3 files are different. Most of the .mp3's have a black icon but some of them (not a lot) have this white icon. When looking at the info of the files they seem to be exactly the same.

The files that have a white icon do not appear on my iPod when i sync them. I do not get a error message or anything, they just don't appear. They do appear in iTunes tho, so as an example, my 'top 25 played' list has 25 songs in my Mac, but only 22 on my iPod.

Can anyone help me with this? Do I maybe need to convert the "white icon files"? Or maybe this has something to do with a iTunes or iPod setting?