Rescue System

If your system won't boot, the "Enable/disable rescue mode" option lets you access the hard drive.

The rescue system is based on Rescatux. After enabling it, boot up and you'll first need to locate the original hard drive by running the command

lsblk

You should see the hard drive devices—for example, /dev/sda1, which should match your disk's size (e.g., 50GB).

Then simply mount the device to a folder, such as /mnt, using:

sudo mount /dev/sda1 /mnt

Make any necessary changes.

Disable rescue mode when you're done.