error: symbol 'grub_calloc' not found on Ubuntu boot [closed]

Question

I am developing a Java application to run on Windows and Linux, instead of virtual machines, I need to use dual boot, however, after updating Ubuntu 20.04 LTS weekly, I'm trying to restart the machine and the terminal appears with an error message:

error: 'grub_calloc' symbol not found.
Entering recovery mode ...
grub rescue>

How to fix this?

Answer 1

You need to reinstall grub to your boot partition, which can be done as follows:

• boot to a linux live system (e.g. Ubuntu Desktop).

• assuming your actual boot partition is /dev/sda1 run the following:

   sudo apt-get update && apt-get install grub2
   sudo mount /dev/sda1  /mnt    
   sudo grub-install --root-directory=/mnt/  /dev/sda 
  

• restart your system, do not forget to remove the live image.