This is not a primarily JUCE issue, but just a note for other Developers.
By one of my customers, my plugin couldn't save its settings into "Music/Audio Music Apps" (this folder should be used, because of Sand-boxing)
The reason was, that another installer, once created the "Audio Music Apps" Folder with root-write permissions only
"drwxr-xr-x 4 root staff 136 May 24 2014 Audio Music Apps"
But then, no other app, can write into this folder.
So beware of it, because the "Music" is in the Home-Directoy of a user, just create the folder with same user as owner.
"drwxr-xr-x 11 username staff 374 2 Nov 2014 Audio Music Apps"