When you use MagicPodDesktop to connect to a real iOS device for the first time, a message dialog box will appear telling you that "codesign is trying to access the key "..." contained in the keychain" and you will be asked to enter a password. There will be times, however, when the password entry will not be successful no matter how many times you enter the password.
In such a case, try a workaround If a password-related error occurs.