[PROBLEM] One folder empty view

[pegaso]

Try the following:

1. Clear system logs (System Config)
2. Regenerate Library database (Library Config)
3. Examine MPD log for errors regarding the Folder you mentioned

Code:

cat /var/log/mpd/log

I checked exactly as you instructed me. Unfortunately, there is nothing suspicious. In the mpd log all files from this folder--->  update: updating NAS/Musica/...... (no error notification). 
BTW. Examining the log I found some corrupt files but all of them in different folders.