Level 1

1 points

Bootcamp - deleted my mac partition accidently

While installing windows onto my mac (which successfully worked) I realised that I had accidently deleted my mac partition and most likely have given the storage to the window's partition. After messing around with some stuff in recovery mode I can no longer load into windows, and whenever I start my computer there is now a folder with a question mark blinking non-stop. Here in recovery mode, I can somehow see all the files and applications I normally had on my macbook before **** hit the fan so I'm guessing I can still fix this without fully installing mac os x again. Oh, and also when I tried installing the mac os x it would not let me and the HD was greyed out. I have no idea how I can use disk utility to fix this so I need help on what to do, and how to get the sudo commands in terminal working so I can post them here to help you guys out.

MacBook Pro with Retina display, iOS 9.2, 2013

Posted on Dec 22, 2015 6:15 AM

38 replies

thechoisn1 Author

Level 1

1 points

Dec 25, 2015 8:48 PM in response to Loner T

I just tried re-installing the OS X again on my external disk and it again comes up with a greyed background with a stop sign in the middle.

Loner T

Level 9

59,536 points

Dec 26, 2015 7:24 AM in response to thechoisn1

Please run a SMC and NVRAM Reset and try again.

Resetting the System Management Controller (SMC) on your Mac - Apple Support

How to Reset NVRAM on your Mac - Apple Support

If the machine reboots after you start the OS X installation on the external disk, before you see the stop sign, press Alt/Option key and check what selections are available.

Do you have a 16GB USB Flash drive?

Based on the GPT output you have a CS volume, but you are missing EFI, and you have Free Space after Recovery HD. You can take a risk and run

diskutil repairDisk disk0

This will recreate EFI, but you may lose your OS X installation. The external disk boot allows you to look at the internal disk and salvage files, before a repairDisk operation is attempted.

thechoisn1 Author

Level 1

1 points

Dec 27, 2015 10:39 PM in response to Loner T

After the reboot, once again, only the external disk called OS X Installer comes up, and also when I type in diskutil repairDisk disk0 into terminal, it says

'Unable to repair this whole disk: the target disk is too small for this operation.'

Loner T

Level 9

59,536 points

Dec 28, 2015 6:49 AM in response to thechoisn1

From Recovery Console, with the eternal disk connected, can you post the output of diskutil list ?

thechoisn1 Author

Level 1

1 points

Dec 29, 2015 4:33 AM in response to Loner T

Loner T

Level 9

59,536 points

Dec 29, 2015 9:52 AM in response to thechoisn1

1. Your external disk is not visible.

2. The sectors 34-49606 contain your EFI partition. This requires Gdisk to fix it.

3. The 1296536 sectors is your Recovery HD, not your Windows installation. This requires Gdisk to fix it.

4. The 39261335 sectors is your Windows partition. This requires Gdisk to fix it.

Gdisk must be installed on a running OSX device. Since OSX does not boot from the internal disk, you require an external disk with OSX installed. If you are unable to install OSX on an external disk, setup an appointment at the nearest Apple store and take an external disk with you. Ask the Genius at the Bar to install OSX on your external disk.

Do not let the Genius touch your internal disk in any way, otherwise you will lose all your data.

You can also use a Linux Live CD to boot your Mac from, which should contain Gdisk.

thechoisn1 Author

Level 1

1 points

Dec 29, 2015 5:21 PM in response to Loner T

If I were to decide that I wanted to just reset my whole macbook and lose all the data, how could that be done?

Loner T

Level 9

59,536 points

Dec 29, 2015 5:36 PM in response to thechoisn1

In the Recovery Console, click on Disk Utility and erase your whole entire disk, and then click on Re-install OS X. If you can figure out the issue with your external installation, you do not need to do this. 😉

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Bootcamp - deleted my mac partition accidently