... happens, if you boot with disabled crypttab, and then invoke later the manual encryption, e,g, remote over ssh: sudo cryptsetup open /dev/disk/by-partuuid/0004a183-01 500go --key-file /etc/500go where PARTUUID=0004a183-01 from crypttab syntax matches /dev/disk/by-partuuid/0004a183-01 here.