This is to fix your errors if the operating system cannot boot.
you will be able to modify your errors in a root console.
I have Ubuntu Server.
When starting the PC, hold down the shift key, esc in some cases.
I had forgotten that grub appears first.
choose recovery mode with the most modern version of so.
Then a screen will appear with options
when you choose root it will ask you for its password.
If you choose root, a console will appear with the root user.
you can fix your problem in a root console.
You should restart the PC, if the error is fixed.
that’s all.