终端 杀死进程命令
To the terminal…

Dauphin:~ james$ ps x | grep iTunes
237 ?? S 0:00.29 /Applications/iTunes.app/Contents/MacOS/iTunesHelper.app/Contents/MacOS/iTunesHelper -psn_0_86037
13970 s000 S+ 0:00.00 grep iTunes
Aha! The iTunes helper application was still running preventing the installation from continuing.

Dapuhin:~ james$ kill 237

注意进程号 有可能是不一样的