Solved! Laptop blank screen when starting with 2nd monitor

Apr 5, 2019
If I leave a second monitor plugged in when I close the lid of my laptop to put it to sleep, both screens are blank when I put the laptop back on. This means I have to force-shutdown the laptop, remove the 2nd monitor, then restart the laptop to get it to work. If I unplug the 2nd monitor before putting the laptop to sleep, it start up fine, but it doesn't if I remove it afterwards.

Does anyone have a solution?
Which laptop model is it?

Reinstall chipset drivers and ACPI driver from the laptop manufacturer´s homepage. Eventually update the BIOS. (to be safe, only flash the BIOS within the BIOS)