athelp
Level 1 (4 points)
Windows Software

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

by Loner T,Solvedanswer
Loner T Loner T
Level 7 (23,828 points)
Safari
A:

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

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athelp

Q: Lost boot ability to OSX

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  • by athelp,

    athelp athelp Jul 29, 2016 10:06 AM in response to athelp
    Level 1 (4 points)
    Windows Software
    Jul 29, 2016 10:06 AM in response to athelp

    BIOS Mode: Legacy

    Right now I'm in:  Command (? for help):

    Do I press 'r' then Enter?

  • by Loner T,

    Loner T Loner T Jul 29, 2016 10:19 AM in response to athelp
    Level 7 (23,828 points)
    Safari
    Jul 29, 2016 10:19 AM in response to athelp

    If you delete GPT4, then W10 will become GPT4. Since you have Legacy Windows, we can recreate the MBR to accommodate the current GPT4, but deleting the partition would require rebuilding the MBR again.

     

    Here is an example of an MBR.

     

    Command (? for help): ?

    b back up GPT data to a file

    c change a partition's name

    d delete a partition

    i show detailed information on a partition

    l list known partition types

    n add a new partition

    o create a new empty GUID partition table (GPT)

    p print the partition table

    q quit without saving changes

    r recovery and transformation options (experts only)

    s sort partitions

    t change a partition's type code

    v verify disk

    w write table to disk and exit

    x extra functionality (experts only)

    ? print this menu

     

    Command (? for help): r

     

    Recovery/transformation command (? for help): ?

    b use backup GPT header (rebuilding main)

    c load backup partition table from disk (rebuilding main)

    d use main GPT header (rebuilding backup)

    e load main partition table from disk (rebuilding backup)

    f load MBR and build fresh GPT from it

    g convert GPT into MBR and exit

    h make hybrid MBR

    i show detailed information on a partition

    l load partition data from a backup file

    m return to main menu

    o print protective MBR data

    p print the partition table

    q quit without saving changes

    t transform BSD disklabel partition

    v verify disk

    w write table to disk and exit

    x extra functionality (experts only)

    ? print this menu

     

    Recovery/transformation command (? for help): o

     

    Disk size is 1954210120 sectors (931.8 GiB)

    MBR disk identifier: 0x028A47A7

    MBR partitions:

     

    Number  Boot  Start Sector   End Sector   Status      Code

       1                     1       409639   primary     0xEE

       2                409640   1449034287   primary     0xAF

       3            1449034288   1450303823   primary     0xAB

       4      *     1450305536   1954209791   primary     0x07

  • by athelp,

    athelp athelp Jul 29, 2016 10:26 AM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Jul 29, 2016 10:26 AM in response to Loner T

    Let's leave the partitions how they are. If we bring back the OSX, I will back it, than erase the other partitions, create a new Bootcamp partition and Install Windows 10 again. Just to be on the safe side.

  • by Loner T,

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

    Since you had to choose between the GPT and MBR with option '2' at the start and you selected GPT, if you run 'w' and confirm 'y', it should make the table a GPT. We can go back into Gdisk and test, before we try to boot OSX.

  • by athelp,

    athelp athelp Jul 29, 2016 10:41 AM in response to Loner T
    Level 1 (4 points)
    Windows Software
    Jul 29, 2016 10:41 AM in response to Loner T

    Loner T, you are a true master

    OSX is back!!!

    Thank you very much for your help. I cannot thank you enough...

     

    Let this be a lesson to all the readers - Backup Backup Backup

  • by Loner T,Solvedanswer

    Loner T Loner T Jul 29, 2016 11:07 AM in response to athelp
    Level 7 (23,828 points)
    Safari
    Jul 29, 2016 11:07 AM in response to athelp

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

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