Level 1

5 points

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

Loner T

Level 9

59,536 points

Apr 9, 2016 5:02 AM in response to ozeegers

Are you able to see the GPT correctly after the reboot?

ozeegers Author

Level 1

5 points

Apr 9, 2016 6:26 AM in response to Loner T

this is the output of gdisk after reboot:

Veerles-MBP:~ vclaeys$ sudo gdisk /dev/rdisk0

Password:

GPT fdisk (gdisk) version 1.0.1

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.

ozeegers Author

Level 1

5 points

Apr 9, 2016 6:18 AM in response to ozeegers

sudo gpt -vv -r show /dev/disk0

gpt show: /dev/disk0: mediasize=750156374016; sectorsize=512; blocks=1465149168

gpt show: /dev/disk0: Suspicious MBR at sector 0

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: error: bogus map

gpt show: unable to open device '/dev/disk0': Undefined error: 0

Loner T

Level 9

59,536 points

Apr 9, 2016 6:39 AM in response to ozeegers

We can create a new GPT and see if it addresses the GPT command issue. In Gdisk, there is 'b'(backup) command that can write to a file. Can you create a backup and move this file to some external storage before we take any further steps?

ozeegers Author

Level 1

5 points

Apr 9, 2016 6:54 AM in response to Loner T

ok, it asked me a filename.... do you where it puts files by default ? Now searching for backupGPT_160409

ozeegers Author

Level 1

5 points

Apr 9, 2016 6:58 AM in response to ozeegers

is this the right command for backing up ?

sudo disk -b backupGPT160409.gpt /dev/rdisk0

ozeegers Author

Level 1

5 points

Apr 9, 2016 7:09 AM in response to ozeegers

Loner T

Level 9

59,536 points

Apr 9, 2016 9:08 AM in response to ozeegers

Run Gdisk and at the interactive promo type 'b'. The file is saved in the directory where you are (i.e. current directory).

ozeegers Author

Level 1

5 points

Apr 9, 2016 9:25 AM in response to Loner T

OK, I managed to back it up and saved to an USB stick....

I put device /dev/disk0 but don't understand why in Disk Utility it says disk0s4 ? Is this correct ?

What can we do next ? Thank you so much !

Loner T

Level 9

59,536 points

Apr 9, 2016 10:23 AM in response to ozeegers

GPT Fdisk allows you to create a new blank GPT and check to ensure it matches what you currently have. This should be done in Internet Recovery, Unfortunately it requires installing OS X on an external drive, instilling GPT Fdisk on the external OS X, and then booting from it and rebuilding it.

Please see

OS X: About OS X Recovery - Apple Support

How to install OS X on an external drive connected to your Mac - Apple Support

ozeegers Author

Level 1

5 points

Apr 9, 2016 12:04 PM in response to Loner T

OK, i am moving files from one external to another to make one external drive completely free to format it (was MSDOS) and install macOS..

maybe i'll change to using mac instead of windows ;-) after Ive recovered my files and emails :-)

ozeegers Author

Level 1

5 points

Apr 10, 2016 5:50 AM in response to Loner T

OK !

I installed osX on my external Seagate drive and installed gdisk.

Then I rebooted from that drive and started terminal...

What next ? ;-)

Loner T

Level 9

59,536 points

Apr 10, 2016 10:21 AM in response to ozeegers

Can you use Gdisk to create a new gpt on disk0 using the start/end/type values? Let me know if you need detailed steps.

ozeegers Author

Level 1

5 points

Apr 10, 2016 10:40 AM in response to Loner T

Yes can you please give me detailed instructions ? I'm not used to using MacOS.. thank you

Loner T

Level 9

59,536 points

Apr 10, 2016 11:00 AM in response to ozeegers

Let me get connected via my Mac. Will post in a couple of hours.

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bootcamp partition renamed untitled after booting in MacOS