How to Uncheck All Songs in iTunes
iTunes is an essential program for owners of Apple devices. By default, the program will sync all songs with an iPhone or iPod whenever one of these devices is attached to your computer. One way to stop all songs from syncing from iTunes to your device is to remove the check mark, or uncheck, all songs in your library. This action can be completed in just a few seconds.
Open iTunes on your computer and click on "Music" under the library section of the left side toolbar.
Hold down the "Control" key on your keyboard (or the "Command" button, on a Mac).
Click on the check mark to the left of one song while still holding down the "Control" key.
Release both the "Control" key and your mouse click at the same time.
Complete the same directions again to reverse the action and recheck all songs.