Then select Troubleshoot -> Startup Repair and select the OS whose bootloader you want to try to repair.Click the Restore System on the installation screen.
The procedure for the automatic repair of the EFI bootloader used in the Windows Recovery Environment (WinRE) is usually useless in such cases. Automatic Windows Bootloader Repair with WinRE
If you only see a black screen with the message “An operating system wasn’t found” when you boot your computer, it’s likely that the Windows bootloader has been completely removed.
