I have a 2014 LS460 with the Mark Levinson stereo. I put mp3s on a usb drive. After it indexed all the folders and songs showed up.
I took the drive out and added some more songs.
Now the songs all show but the folders are greyed out. If I select the song then all the songs in that folder show up.
But The folder display, if I select it it will not show the list of folders like it did the first time. I can use the left and right arrows to scroll through the folders one at a time and selct it so they are all there. Any ideas why the folders list won't show up?

Folders greyed out

All songs show

 

The only thing I can think of is the new files may be corrupt? Don't know why anything should have changed.

 

It takes time for the indexing to occur. I have a 64GB USB drive and it can take 5-10 min to index (this is when the folders will light up). Mine will light up and I can change folders once indexing is complete.