Grub does not find Windows

For security reasons, some Linux distributions set the GRUB configurations in a way that they do not find Windows installations by default. Therefore, some minor adaptations have to be made in order to be able to start Windows from GRUB.

Check if Windows can be found

Check if the command os-prober finds Windows. In case os-prober does not exist, install it as follows:

sudo apt install os-prober

Commit changes in the GRUB configuration

Under Ubuntu the configuration file is /usr/sbin/grub-mkconfig.

Before changing that file, make sure to have a backup:

sudo cp /usr/sbin/grub-mkconfig /usr/sbin/grub-mkconfig-orig

Follow these steps if os-prober shows Windows, but GRUB does not.

• Edit grub-mkconfig
  sudo nano /usr/sbin/grub-mkconfig (in some other distributions /usr/bin/grub-mkconfig)
• Find these lines:
  

  
  # Disable os-prober by default due to security reasons.
  GRUB_DISABLE_OS_PROBER="true"
  

  or

  
  # Disable os-prober by default due to security reasons.
  GRUB_DISABLE_OS_PROBER="auto"
  

• Change true or auto to false
• Exit nano (CTRL+X, Y, Enter)

Update GRUB

Update GRUB via sudo update-grub.

In case you encounter problems booting after applying this workaround, consider checking our article on Linux Boot Repair Tools.