I have Linux Mint 18 Cinnamon installed as the only OS on my Acer Aspire 5750 laptop. I have a BenQ external monitor connected such that I have a dual monitor setup (my laptop screen + BenQ).
When I put the computer into Hibernate and then wake it up, it hangs on boot. What happens is that the laptop screen is black and on the BenQ external monitor I see the Acer logo at first, but then it is partially blocked out by the silhouette of a black rectangle:
Sometimes the display would also contain a non-blinking underscore in the top left corner. Sometimes the BenQ external display is completely black and the laptop's screen in black and contains a non-blinking underscore in its top left corner.
When this happens I proceed to force shut-down the computer (press power button for 5 seconds). Then I turn the computer back on by again pressing the power button, which brings up Grub where I select Linux Mint 18 Cinnamon 64-bit which boots the OS. Interestingly, this restores my session from when I put the computer into Hibernate - so everything is okay! Question: what is up with the hang on boot from which I have to force-restart the computer? How can I fix this?