HuntCN
Level 1 (12 points)
Mac OS X

Q: OS X disk removed, now only have windows 10. How can i get OS X back?

I've recently tried to install Windows 10 on my MacBook pro late 2012, I remembered it's OS X 10.10.5.

I only gave the Windows system around 200GB (mine pc has in total 500GB), and when i came to the stage where the windows installation told me to select a disk to install Windows 10, there were 4 partitions:

1. Disk 0, Partition 1, 600MB

2. Disk 0, Partition 2, 260GB

3. Disk 0, Partition 3, 200MB

4. Disk 0, Partition 4, 190GB (i'm pretty sure that this is the one that i need to install my windows on).

 

However, i tried to select the partition 4, but then a window popped up and told me that the format was not correct, i need to change to the GPT format, which i later looked up on youtube, that i had to go back to the window where it told me to insert the Product Key. (I followed this video on youtube https://www.youtube.com/watch?v=VZqhz2p1OFQ

 

After i typed in all the commands which i realized now that i've cleaned all my OS X disk (because there was only 1 disk shown when i typed in 'list disk' like the guy did in the video, so i did 'clear' and 'convert GPT'), i managed to move on and my windows was started. I did not have any product key.

 

After the Windows set up was ready, i tried to shut down my pc and press ALT-option button when i reopened my pc, and i realized that only 1 disk was available for me, and that is the EFI disk. I reset my pc, but using Windows preferences, it took me about 2 hours to complete the reset, and i was hoping to have my OS X disk back on again after the reset, but after, there was still, only 1 disk available for me to choose, and that is the EFI disk.

I repeated all my steps from above (except converting the disk to GPT format) and installed Windows 10 again, which i am using right now to post this, and try to look for help: How can i delete this Windows 10 and go back to my old OS X disk? (i know i've lost all my data but i had it backed up in my USB drive). Right now i only have Windows 10 on my Macbook Pro, and there is no sign at all of where is my OS X disk or how can i use it.

 

Also at the same time i realized i have lost approximately 30GB on my pc for some strange reasons. Before i used to have 490GB on my mac, now it only shows there are only 460GB in total.

 

Please help! Please ask me questions if my explanation was not accurate for you to understand.  

MacBook Pro, Mac OS X (10.6.1)

Posted on Jun 11, 2016 11:14 AM

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HuntCN

Q: OS X disk removed, now only have windows 10. How can i get OS X back?

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  • Helpful answers

  • by leroydouglas,

    leroydouglas leroydouglas Jun 11, 2016 12:11 PM in response to HuntCN
    Level 7 (22,783 points)
    Notebooks
    Jun 11, 2016 12:11 PM in response to HuntCN

    HuntCN wrote:

     

    I've recently tried to install Windows 10 on my MacBook pro late 2012, I remembered it's OS X 10.10.5.

     

    Did you let  BootCamp create the partition or did you try to do this manually?

  • by HuntCN,

    HuntCN HuntCN Jun 12, 2016 8:46 AM in response to leroydouglas
    Level 1 (12 points)
    Mac OS X
    Jun 12, 2016 8:46 AM in response to leroydouglas

    It has let me to choose how much space i want to give to Windows 10 before my pc restarted automatically, but when i tried to choose the partition i want Windows to be in when i was at the Windows installation progress (it's in the youtube video from the above link). It showed there were 4 partitions, 2 of them were my USB, 1 of them was the OS X, and the other 1 was for Windows. It said i need to have the GPT format, which i chose to convert my original format to it manually, and i thought i deleted all my data on my OS X disk, because when i tried to convert, there were only 1 disk available for me to choose and that disk was 465GB. So i think bootcamp did create the partition, but it didn't turn out to actually separate the disk into 2 partitions.

  • by Eric Root,

    Eric Root Eric Root Jun 12, 2016 8:58 AM in response to HuntCN
    Level 9 (69,659 points)
    iTunes
    Jun 12, 2016 8:58 AM in response to HuntCN

    Try restoring your computer from your backup. You may need to boot into the Recovery Partition, erase the entire drive, and then restore from your backup. Then use Boot Camp Assistant to add the Windows partition.

  • by HuntCN,

    HuntCN HuntCN Jun 12, 2016 11:20 AM in response to Eric Root
    Level 1 (12 points)
    Mac OS X
    Jun 12, 2016 11:20 AM in response to Eric Root

    I have already tried to restore my PC, but using the Windows 10 settings and after there was still one disk available which was the Windows 10.

    By what do you mean backup? I didn't have my Time Machine set up nor any disks has any of my previous data. Can you please explain it more in detail because i am not familiar with it, or maybe send me a link which has some explanation in it?

    I am so sorry if that is too much to ask for.

  • by Eric Root,

    Eric Root Eric Root Jun 13, 2016 11:40 AM in response to HuntCN
    Level 9 (69,659 points)
    iTunes
    Jun 13, 2016 11:40 AM in response to HuntCN

    It sounds like you don't have a backup, so you can't restore anything. It is normally recommended to have backups for when things like this happen.