In base al supporto Apple , "Gestisci manualmente" è un mezzo per utilizzare il tuo iDevice con più computer. Da questo articolo:
Automatic Mode
When your device is set to automatic mode, iTunes automatically
updates your device's music library whenever you connect it to your
computer. iTunes transfers new songs you've added and erases songs
you've removed. The first computer you connect your device to is its
"home" computer. The music library from that computer is copied to
your device. When you connect your device to a different computer, an
alert box appears with this message:
iPod is synced with another iTunes library dialogue
If you want to delete the music library on your device and make the
new computer its "home" computer, choose Erase and Sync. iTunes will
delete all songs and playlists on your device, and then will copy the
music library and playlists from the new home computer to your device.
If you want to move the iTunes Store purchases on your device to the
new computer, choose "Transfer Purchases." The new computer must be
set up with your iTunes Store account and authorized to play your
iTunes Store purchases in order to transfer your iTunes Store
purchases.
Manual Mode
If you want to keep the music library on your device, but copy songs
or playlists from the music library on the second computer, click
Cancel when the dialog box appears, and then set your device to manual
mode
L'articolo ha anche questo avvertimento:
iPod shuffle and iPhone are intended for use with a single computer.
You cannot load music from multiple computers or iTunes libraries onto
iPod shuffle and iPhone like you can with other devices.
D'altra parte, "Sincronizza solo i brani selezionati" ti dà il controllo su quali brani vuoi sincronizzare con iTunes: puoi selezionare i seguenti elementi per sincronizzare la musica da: playlist, artisti, generi o album. Maggiori dettagli possono essere trovati in questo articolo di supporto Apple
.
Se non utilizzi né iPod shuffle né iPhone, puoi combinare entrambe le opzioni per ottenere il massimo controllo sulle opzioni di sincronizzazione della musica.