I'm running Elementary Loki on an Dell Vostro 5480 with Intel Core i7-5500U and a NVIDIA GM108M [GeForce 830M] graphic board, so when I suspend, lock screen or the system automatically lock, and I come back, the screen just stay black, then I need force the system to shut down with the power button. All the drivers was installed. What can I do?
I had a similiar problem and reported it to launchpad, see: https://bugs.launchpad.net/elementaryos/+bug/1628929
Reinstalling elementary directly might fixed this issue for me, but I want to do further testing.
The problem is mostly related to kernel version. Try 4.4.0-36/38 kernel using following commands.I had similar problem but after installing these the problem has been solved. To confirm it, I also reproduced the problem by installing/reinstalling the kernels.
sudo apt install linux-headers-4.4.0-36 linux-headers-4.4.0-36-generic linux-image-4.4.0-36-generic linux-image-extra-4.4.0-36-generic