ubuntu@comp:~$ sudo vgchange -ay /dev/mapper/luks-<HEX VALUES>
  skip_dev_dir: Couldn't split up device name luks-<HEX VALUES>.
  Volume group "luks-<HEX VALUES>" not found
  Cannot process volume group luks-<HEX VALUES>
ubuntu@comp:~$ man vgchange
ubuntu@comp:~$ sudo vgchange -ay /dev/mapper/sda5_crypt
  Volume group "sda5_crypt" not found
  Cannot process volume group sda5_crypt