That made me think about grub, so i reinstalled grub as described here https://help.ubuntu.com/community/Grub2/Installing#Reinstalling_GRUB_2_from_a_Working_System
sudo grub-install /dev/sdX sudo update-grub sudo reboot
and voila, the error message is gone.
That made me think about grub, so i reinstalled grub as described here https:/ /help.ubuntu. com/community/ Grub2/Installin g#Reinstalling_ GRUB_2_ from_a_ Working_ System
sudo grub-install /dev/sdX
sudo update-grub
sudo reboot
and voila, the error message is gone.