Rescue System

If your system fails to boot, the 'Enable/disable rescue mode' option lets you access the hard disk. 

The rescue system is configured with Rescatux. After enabling it, boot up and first locate the original hard disk by running the command:

lsblk

You should notice disk devices like /dev/sda1, which will correspond to your hard disk’s size (e.g., 50 GB).

Next, simply mount the device to a folder, such as /mnt, with the command:

sudo mount /dev/sda1 /mnt

Carry out whatever changes are needed.

When finished, disable rescue mode.