For some reason one of my CentOS 7 boxes decided to nuke itself yesterday, when I powered it on it prompted me with the following error: “failed to open \efi\centos\grubx64.efi”. What I did to fix it is: Boot up a rescue USB, mount the required partitions and chroot. Add a DNS server: $ echo "nameserver *.*.*.*" >> /etc/resolv.conf Enable networking using ifconfig (in my case it was already enabled). Install some additional grub2 modules: $ yum install grub2-efi-modules Reinstall grub, read “/etc/fstab” or “lsblk” command to find it: $ /sbin/grub2-install /dev/boot/partition Reinstall grub: $ yum reinstall grub-efi shim Rebuild grub.cfg file: $ grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg