Something got borked recently on my MBP and now Windows 10 is unbootable - here are the details.
MacBook Pro 2019, macOS 11.2.3, Windows 10 Pro x64 20H2.
- I can see all files on the Bootcamp partition from within macOS.
- The Startup Disk System Preference only shows my macOS volume as a boot option (when things were working normally, both macOS and Windows were startup options).
- In the Startup Security Utility in the MBP Recovery partition, Firmware Password Protection is Off; Secure Boot is set to No Security; Allowed Boot Media is set to Allow booting from external or removable media.
Results of bless
:
%sudo bless --info
Can't access "efi-boot-device" NVRAM variable
When I hold down the Option key at startup, the Windows partition is a boot option. When I select it to boot, I immediately get a blue screen with the message:
Recovery
Your PC/Device needs to be repaired
A required device isn't connected or can't be accessed.
Error code: 0xc000000f
You'll need to use recovery tools...
- I have a bootable flash drive with W10 on it. When I boot from it and attempt Startup Repair - Fix problems that keep Windows from loading, it returns after just a few seconds with the message, "Startup Repair couldn't repair your PC."
I go to the Command Prompt tools option, and here are some repair attempts and the results:
X:\Sources>bootrec /fixboot
Access is denied.
X:\Sources>bootrec /rebuildbcd
Scanning all disks for Windows installations.
Please wait, since this may take a while...
Successfully scanned Windows installations.
Total identified Windows installations: 0
The operation completed successfully.
DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
Disk 0 Online 7663 MB 0 B
Disk 1 No Media 0 B 0 B
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
Volume 0 E DVD-ROM 0 B No Media
Volume 1 C ESD-USB FAT32 Removable 7662 MB Healthy
Volume 2 D Removable 0 B No Media
X:\Sources>bcdedit
The boot configuration data store could not be opened.
The requested system device cannot be found.
I would really prefer not to have to blow away the bootcamp partition and start over from scratch, although that is an option (albeit the final one) - thanks for any assistance.
bootrec /fixboot
writes new boot sector to the system partition. Your Mac EFI boots Windows 10 and therefore does not use the boot sector. – David Anderson Apr 01 '21 at 17:59diskpart
did not show the internal drive when you entered the commandlist disk
. I can identify two possible mistakes. First, you may not have correctly created the Windows 10 USB installer. Second, the required driver did not load before entering thediskpart
command. – David Anderson Apr 01 '21 at 19:33bcdedit
says everything's fine. So there's something corrupted before Windows even boots - somehow the necessary drivers aren't being loaded with Windows. – Conrad Apr 02 '21 at 00:15install.wim
file that exceeds the 4 GB limit imposed by the FAT32 format. This is why the Windows 10 installer USB flash drive needs to be ExFAT formatted. The Microsoft Media Creation Tool downloads ainstall.esd
file instead, which is under the 4 GB limit. – David Anderson Apr 02 '21 at 04:40