Unable to boot Windows from Bootcamp

Question

Opi-Opi Author

Level 1

11 points

Unable to boot Windows from Bootcamp

My Hardware:

iMac Retina 5K, 27inch, Late 2015, i7, 16GB RAM, 512GB SSD with APFS

Software:

High Sierra v 10.13.6

Bootcamp:

Windows 10, NTFS

My Problem:

For the last 3 weeks or so, I am unable to start up in Bootcamp.

The setup had been working ok for the last 5+ years, on 2 iMacs and various

macOS and Windows versions.

When selecting the Bootcamp as the Startup Disk, error message says:

“You can’t change the startup disk to the selected disk.

The bless tool was unable to set the current boot disk.”

I reset NVRAM etc, nothing helped. Installed Mojave on an external SSD drive and booted up from that; then tried selecting Bootcamp from there - same ‘bless tool…’ message.

Where is the file, that contains the ‘bless tool’ that allows me to boot up via the Bootcamp partition?

How can I repair my system?

Please Help!!

Opi

iMac (27-inch, Late 2012), OS X El Capitan (10.11.1)

Posted on Aug 10, 2018 9:24 AM

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Answer 1

Loner T

Level 9

59,536 points

Aug 10, 2018 11:42 AM in response to Opi-Opi

Bless should not used to boot Windows on a 2015 Mac. If you reboot and hold Alt/Option and see a selection for Windows, can you boot from it?

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Answer 2

Opi-Opi Author

Level 1

11 points

Oct 22, 2018 5:53 PM in response to Loner T

Hi Loner,

I was, on and off, busy updating things.

Below is a synopsis of how it went; I post the 12 screenshots in 3 further ‘post-batches’ (not sure how many I can attach to a post).

After running a corrected diskpart command (picture 1), ensuring C was the NTFS Bootcamp, I ran bcdboot C:\Windows (pic 2).

The answer was ‘Boot files successfully created’.

The command bcdedit then showed the Windows Boor Manager and Boot Loader data.

Exiting Terminal showed a new option “Continue, exit and continue to Windows 10” (pic 3). That was followed by Windows updates being installed, the Log-In screen and the Windows Desktop (pics 4-6) all within 16 minutes!

Pic 7 shows the update history. It seems things went wrong after the 7/7/2018 update, which ties up with Bitdefender showing a 106 days gap in updates.

MS Office 2010 then tried to reinstall, but failed (pic 8-9).

I then tried to track down file ProPrWW.CAB unsuccessfully. I removed Office 2010 and installed my old MS Office 2003, where I still had the DVD (pics 10-12).

Switched back and forth between Bootcamp and H-Sierra several times without failure. However, BC to HS means selecting shutdown on BC, then rebooting with depressed Option key and selecting macOS from screen.

HS to BC the same way, as Preference/Startup Disk window does NOT display the Bootcamp!

Strangly enough, my Mojave installation in Container disk2 does show the Bootcamp icon and lets me select it as the Start up disk. Weird. Any thoughts, Loner?

Thanks again!

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Answer 3

Loner T

Level 9

59,536 points

Aug 12, 2018 6:58 AM in response to Opi-Opi

Can you run

diskutil mount disk0s1

and check if you have a Microsoft folder under /Volumes/EFI. A 2015 Mac only supports an EFI install of Windows. We need to check the BCD to validate that the Windows boot manager is pointing to the correct location.

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Answer 4

Loner T

Level 9

59,536 points

Aug 13, 2018 9:02 AM in response to Opi-Opi

Can you use Re: Setboot? Formerly bless? Command line OS switching? as a reference to run the bless and test? The example is for a 2012 Mac, which supports legacy BIOS. Your 2015 iMac does not support legacy BIOS, which is a significant difference.

Also, you have the EFI partition - disk0s1 - which is not mountable. Before you run bless, can you run

diskutil repairDisk disk0

and post the output?

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Answer 5

Loner T

Level 9

59,536 points

Aug 24, 2018 4:04 PM in response to Opi-Opi

In the Command prompt window run diskpart and ensure C: is pointing to the proper volume. X: typically points to the external boot device and should not be used. Run

bcdboot C:\Windows /s S: /f ALL

See the BCDBoot link and the description under the /f qualifier.

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Answer 6

Loner T

Level 9

59,536 points

Aug 11, 2018 8:16 AM in response to Opi-Opi

Can you post the output of

sudo systemsetup -liststartupdisks

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Answer 7

Loner T

Level 9

59,536 points

Aug 11, 2018 8:27 PM in response to Opi-Opi

Post the output of

sudo bless --info

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Answer 8

mgdb

Level 1

8 points

Sep 2, 2018 11:21 AM in response to Opi-Opi

I prefer this option, hope that can help you and others.

Read all first and don't do this if you are not 100% confident.

*Have at hand Windows 10 Iso and WIN TO USB APP

*You must be logged in a windows pc to achieve this.

*An Ssd or Hd external drive with at least 250gb

*Bootcamp mac hardware drivers in a pen drive or external usb storage device

*Be extremely careful when dealing with partitions, it requires certain knowledge.

1-Create 2 partitions: 1 of 5/6gb as primary or system formatted in FAT 32, the other one with the remaining storage formatted as NTFS

2-Run WIN TO USB app, load windows 10 iso when asked, then choose destination new drive, last screen you must select the smaller partition efi fat 32 as system and the other one,ntfs (bigger partition) as boot click continue.

Now the process of creating Windows to go in external drive begin. Wait until everything is done, eject new drive and plug it in a mac.

Turn your mac on having pressed option key until existing drives appear. Choose the one marked as "EFI", this is the responsible to load windows.

If everything went fine you must follow all the setup screens in windows 10 until everything is configured-

Another last thing regarding hardware drivers: If you see that one particular hardware is not working go to bootcamp folder which I have in a pen drive and run the bootcamp.exe. This will install all mac hardware drivers in order to make it 100 % compatible and operative with windows.

Hope this will help, I tried a lot with different workarounds, neither of them worked for me.

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Answer 9

Loner T

Level 9

59,536 points

Aug 13, 2018 4:18 PM in response to Opi-Opi

Can you temporarily uninstall Paragon and then test?

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Answer 10

Loner T

Level 9

59,536 points

Oct 21, 2018 3:36 PM in response to Opi-Opi

Can you post the output of

bcdedit

bcdboot C:\Windows

Also, check in diskpart, if C: is actually assigned to the Windows partition.

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Answer 11

Loner T

Level 9

59,536 points

Aug 21, 2018 8:12 PM in response to Opi-Opi

BCD is a binary 'hive' used by Windows. Textedit will corrupt it. The two full paths show templates, so these are not correct files.

At this point, we should use bcdboot to build a new BCD in C:\Boot\EFI.

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Answer 12

Loner T

Level 9

59,536 points

Oct 24, 2018 4:23 AM in response to Opi-Opi

Opi-Opi wrote:

Switched back and forth between Bootcamp and H-Sierra several times without failure. However, BC to HS means selecting shutdown on BC, then rebooting with depressed Option key and selecting macOS from screen. HS to BC the same way, as Preference/Startup Disk window does NOT display the Bootcamp!

HS may have issues with switching. See Switch between Windows and macOS with Boot Camp - Apple Support .

Opi-Opi wrote:

Strangly enough, my Mojave installation in Container disk2 does show the Bootcamp icon and lets me select it as the Start up disk.

Is Mojave also installed on the same internal disk as HS and Windows? Can you post the output of

diskutil list

from macOS Terminal?

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Answer 13

Loner T

Level 9

59,536 points

Oct 25, 2018 1:11 AM in response to Opi-Opi

Back up your BCD, try to change the Partition=C: for osdevice and device to be the same as the path in Windows Boot Manager entry (\\Device\...) and test. Since you have two macOS installations, the C: assignment is incorrect for HS.

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