User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:41.0) Gecko/20100101
Firefox/41.0
Build Identifier: 

I've got a laptop with external monitor. Configured with the KDE Configure
Desktop app to be "above" the laptop screen.
When leaving from work I unplugged the monitor, closed the laptop lid and later
at home when it resumed only got a black screen. Restarting didn't help - I got
the startup splash and brief glimpse of X.org startup screen and then it turned
black again.

After much testing I figured that the file
~/.local/share/kscreen/8f27e66f2df16668f11cfb00c42a0786 contained section:

        "pos": {
            "x": 0,
            "y": 1080
        },

Which turned out to be the problem. Apparently offset below the now-unplugged
external monitor. Once I changed 1080 to 0 and restarted laptop it came up all
right.

IMO kscreen should be more intelligent and figure out that the recorded screen
configuration doesn't make sense and readjust the coordinates.

Reproducible: Sometimes