Rescue System

If your system refuses to start up properly, the "Enable/disable rescue mode" feature grants you access to the hard disk. 

The rescue environment is powered by Rescatux. Once you switch it on, boot the machine, and you’ll need to locate the original hard disk by entering this command

lsblk

You should then see the hard disk devices listed—for instance, /dev/sda1—which ought to correspond to your disk’s capacity (e.g., 50 GB).

Next, simply mount the device to a folder like /mnt using

sudo mount /dev/sda1 /mnt

Carry out any adjustments you need.

Turn off rescue mode once you’ve finished.