PS C:\WINDOWS\system32> mbr2gpt /validate /disk:0 /allowfullos MBR2GPT: Attempting to validate disk 0 MBR2GPT: Retrieving layout of disk MBR2GPT: Validating layout, disk sector size is: 512 bytes MBR2GPT: Validation completed successfully PS C:\WINDOWS\system32> mbr2gpt /convert /disk:0 /allowfullos MBR2GPT will now attempt to convert disk 0. If conversion is successful the disk can only be booted in GPT mode. These changes cannot be undone! MBR2GPT: Attempting to convert disk 0 MBR2GPT: Retrieving layout of disk MBR2GPT: Validating layout, disk sector size is: 512 bytes MBR2GPT: Trying to shrink the OS partition MBR2GPT: Creating the EFI system partition MBR2GPT: Installing the new boot files MBR2GPT: Performing the layout conversion MBR2GPT: Migrating default boot entry MBR2GPT: Adding recovery boot entry MBR2GPT: Fixing drive letter mapping MBR2GPT: Conversion completed successfully Call WinReReapir to repair WinRE MBR2GPT: Failed to update ReAgent.xml, please try to manually disable and enable WinRE. MBR2GPT: Before the new system can boot properly you need to switch the firmware to boot to UEFI mode!