Identify the resolution that your VirtualBox environment supports.
Reboot the system and hit ‘c’ when the grub windows appears appears to access grub console. In grub console, enter the following command to see a list of resolutions (eg, 1024x768x32):
Edit the grub configuration file
/etc/default/grub. Uncomment the following line in the file.
Replace the resolution with the one appropriate for your environment.
Save the file. Then update your grub configuration by running:
Restart your virtual machine again