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bootcamp partition renamed untitled after booting in MacOS

Can anybody please help me ?

I had succesfully installed Windows 10 on my Macbook Pro and ran Windows already several weeks smoothly.

Unfortunately I did not make a backup of my windows files yet.

Today when I booted to El Capitan to connect my iPad to iTunes Windows gave me a message that it needed repair when I tried to reboot to the bootcamp Windows version.

It did not succeed in repairing and only gave my an advanced options menu.

I booted back into MacOS to find that the windows partition was renamed to 'Untitled' and that no files were visible in Finder.

I than ran Disk Utility and selected First Aid on this partition, I thought this was read only to check for disk errors.

Now when booting from Windows it says no operation system available and Disk Utility shows 496 GB empty space on this partition !

I hope not all my files are lost !!

What can I do to repair the bootcamp partition ? I tried to install setup bootcamp files on USB but cannot boot from USB (does not show the USB drive)

thank you !

Olivier

MacBook Pro, OS X El Capitan (10.11.3), Bootcamp Windows 10

Posted on Apr 5, 2016 11:34 AM

297 replies

ozeegers Author

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Apr 15, 2016 12:51 PM in response to Loner T

OK too enthousiastic.... I could complete steps 3 and 4 and the MacBook booted from bootcamp but i get this blue screen.... Should we proceed with the windows ISO DVD ?

ozeegers Author

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Apr 15, 2016 12:53 PM in response to ozeegers

ozeegers Author

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Apr 15, 2016 1:09 PM in response to ozeegers

I think this is the same screen as I saw the first time when I rebooted from osX into Windows.

I then selected F8 and let it repair the startup and it ended in saying no operating system.

Loner T

Level 9

59,536 points

Apr 15, 2016 1:20 PM in response to ozeegers

You will need to rebuild the Windows BCD. It is corrupted. Can you use 0x0000034 BCD Error Bootcamp, No Startup Repair as a reference and rebuildBCD using Bootrec.exe?

You now have a different partition layout from the last time you had an issue.

ozeegers Author

Level 1

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Apr 15, 2016 1:31 PM in response to Loner T

Sorry but I can't find what you mean in the link?

Can you provide me with details? Thank you for helping me.

I looked up this myself:

Use Windows 8 bootable DVD or USB and boot.

Select option to repair your system instead of installing.

Go to command prompt (in advanced options) and hit following commands to repair MBR.

bootrec /fixmbr

bootrec /fixboot

bootrec /rebuildbcd

Press [y] when system asks you to accept.

Exit

Now, use option: Refresh your PC in advanced option

Reboot

My problem is solved ( 0xc000000e). Try for yours.

Loner T

Level 9

59,536 points

Apr 15, 2016 1:47 PM in response to ozeegers

The other thread has a different error. Is your Windows back and running normally?

ozeegers Author

Level 1

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Apr 15, 2016 1:54 PM in response to Loner T

No but I managed to boot from Windows 10 ISO DVD and into command prompt

Here I see my files on C: with my user directory...

How do I rebuild the bcd from here?

Loner T

Level 9

59,536 points

Apr 15, 2016 1:57 PM in response to ozeegers

You will need to use diskpart to assign a drive letter to the EFI partition. Once you assign a drive letter, you can use https://support.microsoft.com/en-us/kb/927392 and use /rebuildBCD. Use the correct drive letter where your BCD is, not the C: drive.

ozeegers Author

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Apr 15, 2016 2:19 PM in response to Loner T

I don't understand why c: isn't the correct drive. Can you give me steps for using disk part?

In command prompt?

Loner T

Level 9

59,536 points

Apr 15, 2016 5:56 PM in response to ozeegers

On some Macs, the Microsoft EFI files are stored in the Mac's EFI partition. This is why you will need to assign a drive letter in diskpart. This is usually the S: drive used during the installation.

In Command Prompt in Windows Recovery, type bcdedit and check what you get back.

ozeegers Author

Level 1

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Apr 16, 2016 12:14 AM in response to Loner T

drives available are c: (windows) d: (DVD) and x: (windows)

ozeegers Author

Level 1

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Apr 16, 2016 12:26 AM in response to ozeegers

should i do the following ?:

bcdedit /export C:\BCD_Backup
c:
cd boot
attrib bcd -s -h -r
ren c:\boot\bcd bcd.old
bootrec /RebuildBcd

Loner T

Level 9

59,536 points

Apr 16, 2016 6:38 AM in response to ozeegers

Can you run diskpart and look at the available disk0 volumes? You should see an EFI entry. Here is an example.

ozeegers Author

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Apr 16, 2016 7:13 AM in response to Loner T

Loner T

Level 9

59,536 points

Apr 16, 2016 7:10 AM in response to ozeegers

Looking at this in a headstand (just kidding). The hidden EFI is 300MB, where it is usually 200MB. You posted this earlier.

1: EFI EFI 209.7 MB disk0s1

Let us ignore it. Assign a letter to the EFI partition - https://technet.microsoft.com/en-us/library/cc757491(v=ws.10).aspx . Once a drive letter is assigned to this device, use the assigned drive letter, not C:, to rebuildBCD. Test.

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bootcamp partition renamed untitled after booting in MacOS