I just done a full system upgrade (pacman -Syyu) and after a reboot, GDM display a “OOPS …error” but managed to get back to graphical login prompt. But no way to logon (always tell me password is wrong) even if keymap shown is fine.
So i done ALT-F2, logged into root and executed :
grub-mkconfig -o /boot/grub/grub.cfg
Everythings back to normal.
Is it documented somewhere that for some system upgrade, a manual reinstallation of grub is required ?