Hi I am not a linux pro, but for me a quick fix what worked was to disable Windows boot. basically everytime windows boot it puts itself as priority, but cannot any more this way. I would then use the grub menu at boot to select what os i needed. I use mint but since both are based on ubuntu should work in the same way. found this online, more or less what i did: https://unix.stackexchange.com/questions/241809/grub2-gone-every-time-i-boot-windows-10 https://unix.stackexchange.com/questions/68581/how-can-i-prevent-windows-from-overwriting-grub-when-using-a-dual-boot-machine