Use this guide to repair the UEFI boot loader in windows that the Sierra installation broke, be sure to follow the guide that corresponds to your version of Windows.
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Apple breaks the UEFI partition while installing Sierra, use this guide to repair the UEFI boot loader in windows that the Sierra installation broke, be sure to follow the guide that corresponds to your version of Windows.
Use this guide to repair the UEFI boot loader in windows that the Sierra installation broke, be sure to follow the guide that corresponds to your version of Windows.
https://neosmart.net/wiki/fix-uefi-boot/#Fix_UEFI_Boot_in_Windows_8_81_or_10