Ubuntu 16.04 Dual Boot Windows 10 boots to black screen unless I boot windows first
Solution 1:
Open a terminal after Ubuntu has booted to your desktop. Ctrl-Alt-t is the easiest way to open it.
Open the grub settings file with sudo:
sudo nano /etc/default/grub
Go down to the blank line after
#GRUB_GFXMODE=640x480
press Enter and enter
GRUB_GFXPAYLOAD_LINUX=keep
The position in the file doesn't actually matter, it's just most logically placed there.
close the file with CtrlwCtrlx.
Run sudo update-grub in the terminal. Reboot.