Unlock screen with device manager so im trying to unlock my galaxy s4 screen, using google device manager, or something similar (any suggestion ?). cuz my screen recently cracked a i wanna get backup from all my data and reset it before i change the screen entirely. but an app like "Kies" requires the screen to be unlocked in order to enable any file transfer! can anyone help me?
Unlocking the screen from outside is not possible. (without root privileges).

If you have a custom recovery installed then you can boot into it and make a backup via adb shell