Hello Javiermnb, Here is a link to the steps I have done to resolve this issue.
Have a read through this link, it is very easy as long as you get the spelling and spaces correctly. While I used a different link this particular link is very concise and clear. I do not know why I got this same message on two of the laptops which I use (older donated laptops I use with youth for study purposes), however both are still working fine and only on one did it occur a second time and again the steps resolved the issue.
https://prognotes.net/2018/04/linux-mint...t-at-boot/
NOTE: in my case I used fsck /dev/sda1 (in my notes I have that you can start by typing only fsck and press enter and then it will show you sda 1/2/3/4/ or 5 (use the one it shows).
Hope this helps, let me know if you have questions and I will try to answer them from my experience.