Upgraded to High Sierra, used Disk Utility, now Windows 10 won't boot

Macbook Air Mid-2011

Perfectly working state this morning:

Windows 10 x64 (upgraded in place from Windows 7 x64 which was created using standard Bootcamp steps in 2011, the upgrade was 3 years ago and was using standard windows process without having to mess with Bootcamp or do anything special).

Windows is the primary OS and machine has been running fine for years. Today I boot into OS X (I do this once a year for updates etc) and install High Sierra and to make some space, I use Disk utility (and do NOT touch the Windows partition), OS X only.

High Sierra successfully installs but when I try to boot back into windows, it just shows a white screen. Booting into OS X is working fine.

The Bootcamp partition still exists and is visible but the MBR is gone or GPT corrupted.

Contacted Apple Support online and they initially stuck with High Sierra isn't compatible with your device (wrong!), Hung up, called again and this time they redirected me to Nerdr article steps (http://nerdr.com/bootcamp-partition-lost-repairing-mac-partitions/) after the initial diagnostics that took an hour. I realise those steps were a mistake. Went to the Apple Store and they said they couldn't help with Boot Camp issues and that it looked like it was a High Sierra issue not Disk Utility (since High Sierra "moves stuff around"). We also tried to understand (but did not implement) couple of other threads where the issues were solved by Christopher Murphy and Loner T, but it was tough to figure out since some of the instructions seemed different:

Repairing Boot Camp after creating new partition

Windows 7 bootcamp partition not bootable after updating to 10.10.3

Repairing Bootcamp after resizing partition

Bootcamp not bootable after partitioning

Bootcamp Partition not bootable after resizing partition on HD

Repairing Boot Camp after creating new partition

Had too many doubts about those. Loner T made it clear not to follow Nerdr instructions but sometimes fdisk was used (built in?) whereas other times gdisk was.

System integrity is already disabled (followed Apple store person's instruction though they couldn't do it themselves coz not allowed). However sudo 'anything' always gives 'command not found' in the recovery terminal.

I'm tech literate and will follow instructions (unfortunately even when they are wrong) but am entirely unfamiliar with OS X and out of my depth here. Have used terminal in Linux and Cmd/Powershell in Win so willing to try anything at this point. I'd post the results of diskutil list but I have no idea how to copy it off of the Recovery and paste here.

OS X still boots fine and Bootcamp partition still exists. I really need to recover this (its not just Data but 400 tabs in browsers with Data I was working on that can't easily be copied).

MacBook Air, macOS High Sierra (10.13.6), null

Posted on Jul 16, 2018 4:57 AM

Similar questions

21 replies

Jul 16, 2018 11:53 AM in response to Loner T

I had already disabled it as part of Apple Support steps. I have rebooted multiple times since, would it have auto re-enabled?

Jul 16, 2018 12:04 PM in response to VineetShrivastava

Just saw your latest message, its disabled now.

Stuart423

Level 6

9,264 points

Jul 16, 2018 5:09 AM in response to VineetShrivastava

Please run Etrecheck and post the results here. https://etrecheck.com

1. Download, open Downloads folder, click it to open, then select 'open'

2. Click on the bouncing Etrecheck icon in the dock

3. Choose a problem from the popup menu, then start Etrecheck in the dialog box

4. Click 'share report' in the toolbar and copy to clipboard

5. Paste the clipboard here

Once we get a look at what's going on with your system, we might be better able to come up with something helpful.

Loner T

Level 9

59,536 points

Jul 16, 2018 12:16 PM in response to VineetShrivastava

VineetShrivastava wrote:

I apologise for the stupidity in between....

No worries. 😉

VineetShrivastava wrote:

Disk: /dev/disk0 geometry: 14751/255/63 [236978176 sectors]

Signature: 0xAA55

Starting Ending

#: id
cyl
hd sec -
cyl
hd sec [ start - size]

------------------------------------------------------------------------

1: EE 1023 254
63 - 1023 254
63 [ 1 -
236978175] <Unknown ID>

2: 00 0
0
0 - 0
0
0 [ 0 - 0] unused

*3: 07 0
0
0 - 0
0
0 [ 0 - 0] HPFS/QNX/AUX

4: 00 0
0
0 - 0
0
0 [ 0 - 0] unused

This is an invalid MBR. You will need to recreate the MBR using the Rebuild MBR section of Re: El Capitan has deleted my bootcamp windows partition. Do not modify the current GPT. The steps you have used only change the bootability of an already existing MBR entry, but does not create one.

Jul 16, 2018 1:07 PM in response to Loner T

Last login: Tue Jul 17 00:01:25 on ttys000

Vineets-MacBook-Air:~ Vineet$ Sudo gdisk /dev/rdisk0

Password:

GPT fdisk (gdisk) version 1.0.4

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Command (? for help): p

Disk /dev/rdisk0: 236978176 sectors, 113.0 GiB

Sector size (logical): 512 bytes

Disk identifier (GUID): 000033B4-45FD-0000-664D-000010580000

Partition table holds up to 128 entries

Main partition table begins at sector 2 and ends at sector 33

First usable sector is 34, last usable sector is 236978142

Partitions will be aligned on 8-sector boundaries

Total free space is 2021 sectors (1010.5 KiB)

Number
Start (sector) End (sector)
Size Code
Name

1 40 409639
200.0 MiB
EF00
EFI system partition

2 409640 75898879
36.0 GiB AF0A
Customer

3 75898880 236976127
76.8 GiB 0700
BOOTCAMP

Command (? for help): r

Recovery/transformation command (? for help): o

Disk size is 236978176 sectors (113.0 GiB)

MBR disk identifier: 0x00004B39

MBR partitions:

Number
Boot
Start Sector
End Sector
Status Code

1 1 236978175
primary 0xEE

Recovery/transformation command (? for help): h

WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one,

just hit the Enter key at the below prompt and your MBR partition table will

be untouched.

Type from one to three GPT partition numbers, separated by spaces, to be

added to the hybrid MBR, in sequence: 2 3

Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): y

Creating entry for GPT partition #2 (MBR partition #2)

Enter an MBR hex code (default AF):

Set the bootable flag? (Y/N): n

Creating entry for GPT partition #3 (MBR partition #3)

Enter an MBR hex code (default 07):

Set the bootable flag? (Y/N): y

Unused partition space(s) found. Use one to protect more partitions? (Y/N): n

Recovery/transformation command (? for help): o

Disk size is 236978176 sectors (113.0 GiB)

MBR disk identifier: 0x00004B39

MBR partitions:

Number
Boot
Start Sector
End Sector
Status Code

1 1 409639
primary 0xEE

2 409640 75898879
primary 0xAF

3 * 75898880 236976127
primary 0x07

Recovery/transformation command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING

PARTITIONS!!

Do you want to proceed? (Y/N): y

OK; writing new GUID partition table (GPT) to /dev/rdisk0.

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Warning: The kernel may continue to use old or deleted partitions.

You should reboot or remove the drive.

The operation has completed successfully.

Vineets-MacBook-Air:~ Vineet$

One thing deviated from script, the bold/underline/italics line about unused partitions and using them to protect. I selected no.
Rebooting now to perform tests

Loner T

Level 9

59,536 points

Jul 16, 2018 8:47 PM in response to VineetShrivastava

Consider a tool like Winclone.

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Upgraded to High Sierra, used Disk Utility, now Windows 10 won't boot