the root filesystem requires a manual fsck
fsck exited with status code 4
the root filesystem on /dev/mapper/pve-root requires a manual fsckrun fsck manually
initramfs fsck
ubuntu fsck repair
initramfs fsck not found
dev/sda1 contains a filesystem with errors

You need space between command and argument. The command is fsck , and the argument is the device /dev/sda1 . Try fsck /dev/sda1 . Ubuntu 16.04 startet nIcht - root filesystem requires manual fsck "fsck/ dev/ sda1" folgen soll und den Fehler damit beheben kann?