Q: Lost boot ability to OSX

So I had OSX and a working second partition with win 10 on it installed with Bootcamp. Both were working fine. Then I created a third partition through Disk utility. Then I attempted to boot to win 10 and got an error:

PC Needs to be repaired, File: \Windows\system32\winload.exe, Error Code: 0xc000000e

And that I need to use a win 10 recovery disk to fix it.

so I made a recovery USB and boot into it and repaired the windows 10 partition. The recovery USB was made from my home PC.

But after doing that my OSX partition completely disappeared. I'm able to boot into windows but lost the OSX partition and cannot login to it.

Can somebody please help me to restore the OSX partition?

Thank you in advance!

Posted on Jul 28, 2016 11:41 PM

I have this question too

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Loner T

Level 7 (23,828 points)

Safari

Excellent. Please ensure you can switch between OSX and Windows and back up both OSes before you start rebuilding the Mac.

Posted on Jul 29, 2016 11:07 AM

Q: Lost boot ability to OSX

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Page 1

by Kappy,

Kappy Jul 28, 2016 11:48 PM in response to athelp
Level 10 (270,928 points)

Desktops

Jul 28, 2016 11:48 PM in response to athelp
Install Yosemite or El Capitan from Scratch

Backup if possible before continuing.

Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:
Select Disk Utility from the Utility Menu and click on Continue button.
When Disk Utility loads select the volume (indented entry, usually Macintosh HD) from the Device list.
Click on the Erase icon in Disk Utility's main window. A panel will drop down.
Set the Format type to Mac OS Extended (Journaled.)
Click on the Apply button, then wait for the Done button to activate and click on it.
Quit Disk Utility and return to the Utility Menu.
Select Reinstall OS X and click on the Continue button.
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by Loner T,

Loner T Jul 29, 2016 5:15 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 5:15 AM in response to athelp

If you do not want to start from scratch as Kappy has indicated, then How to install OS X on an external drive connected to your Mac - Apple Support and boot from this external disk. Do not try to repair/partition your internal disk, otherwise it will get worse.
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by athelp,

athelp Jul 29, 2016 7:09 AM in response to Kappy
Level 1 (4 points)

Windows Software

Jul 29, 2016 7:09 AM in response to Kappy

I have lots of data that I need on the OSX. Does installing from scratch will wipe the previous OSX?
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by athelp,

athelp Jul 29, 2016 7:13 AM in response to Loner T
Level 1 (4 points)

Windows Software

Jul 29, 2016 7:13 AM in response to Loner T

Hey Loner T, I saw your guide:
Lost boot ability to OSX and Windows 10

Is that something that we can do in my case?
I'm trying not to loose all the data I have on the OSX.
My equipment is:
Macbook pro with the issue. I have win 10 installed and running on it
a second home PC
8 GB USB
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by Loner T,

Loner T Jul 29, 2016 8:19 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 8:19 AM in response to athelp

athelp wrote:

I have lots of data that I need on the OSX. Does installing from scratch will wipe the previous OSX?

You are not touching the internal disk, but installing on an external disk and upgrading it to match the version on your internal disk and booting from this external disk.
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by Loner T,

Loner T Jul 29, 2016 8:22 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 8:22 AM in response to athelp

athelp wrote:

Hey Loner T, I saw your guide:

Lost boot ability to OSX and Windows 10

Is that something that we can do in my case?

I'm trying not to loose all the data I have on the OSX.

My equipment is:

Macbook pro with the issue. I have win 10 installed and running on it

a second home PC

8 GB USB

What year/model is your Mac? Is Windows 10 bootable?
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by athelp,

athelp Jul 29, 2016 8:31 AM in response to Loner T
Level 1 (4 points)

Windows Software

Jul 29, 2016 8:31 AM in response to Loner T

Windows 10 is bootable.
Macbook pro from last year Model A1398
The OS X on the lost MAC partition is the new OS X updated couple days ago
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by Loner T,

Loner T Jul 29, 2016 8:41 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 8:41 AM in response to athelp

Boot into Windows and install GPT Fdisk and lets us take a look at the GPT output.

Please start at Re: Lost boot ability to OSX and Windows 10 post and post a screen output from Gdisk using Admin CMD window.
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by athelp,

athelp Jul 29, 2016 9:01 AM in response to Loner T
Level 1 (4 points)

Windows Software

Jul 29, 2016 9:01 AM in response to Loner T
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by athelp,

athelp Jul 29, 2016 9:07 AM in response to athelp
Level 1 (4 points)

Windows Software

Jul 29, 2016 9:07 AM in response to athelp
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by Loner T,

Loner T Jul 29, 2016 9:10 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 9:10 AM in response to athelp

Please do not write anything via Gdisk. Use 'q' to quit' and run it again and choose Option 2 in the first question. Once you have chosen GPT, use 'p' command.
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by athelp,

athelp Jul 29, 2016 9:20 AM in response to Loner T
Level 1 (4 points)

Windows Software

Jul 29, 2016 9:20 AM in response to Loner T
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by Loner T,

Loner T Jul 29, 2016 9:53 AM in response to athelp
Level 7 (23,828 points)

Safari

Jul 29, 2016 9:53 AM in response to athelp

Are you planning to merge GPT4 and GPT5? GPT6 is 2700 - Windows RE. Please post the the output of 'r' (Recovery Menu) -> 'o' (Print MBR) command.

Can you run msinfo32 and check BIOS Mode?
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by athelp,

athelp Jul 29, 2016 9:58 AM in response to Loner T
Level 1 (4 points)

Windows Software

Jul 29, 2016 9:58 AM in response to Loner T

No. GPT5 is where win 10 at. I don't need GPT4 anymore. All I need is the OS X back so I can backup it and the win 10 on GPT5.
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