Unable to format unformatted partition on OS X Sierra

Question

Level 1

15 points

Unable to format unformatted partition on OS X Sierra

Hi guys,

I have a problem with formating (or doing anything with) unformatted partition on OS X Sierra. While setting up my MacBook for the first time, I had some issues while updating to HighSierra so I was restoring it back on Sierra (MacBook originally came with Sierra), so I created parition of 200 GB in order to finish the process.

I managed to get back to Sierra and use my MacBook normally, but now I can't do anything with this 50 GB of extra space which is just hanging there. Is there a way to format this partition so I can use it, but without deleting everything from MacBook, merging partitions and then installing everything from the beginning, because time is issue here and I can't afford going through this process at the time.

If I would be able to somehow format this partition so I can use it, I would be super happy. I hope somebody can help. Sending you screen shot so you can see what's the problem.

Thanks in advance!

MacBook Pro with Retina display, macOS Sierra (10.12.6)

Posted on Mar 1, 2018 3:50 AM

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Answer 1

Eric Root

Level 10

684,027 points

Mar 1, 2018 8:40 AM in response to Govindadas

You can make a bootable USB stick to install using this free program which will do all the work for you.

Bootable USB Flash Drive – Diskmaker X oruse Apple’s method Create a bootable installer for OS

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Answer 2

keg55

Level 6

11,743 points

Mar 1, 2018 8:07 AM in response to Govindadas

The issue to me is when you created your 200GB partition/volume that was a slice after the beginning of the disk. So, if you're trying to merge the 50GB in with it you can't until you erase the 200GB volume. Then, you can merge them into one.

I would suggest this:

Create a Time Machine back up Mac OS SSD.

Restart your Mac using the Alt/Option key and select your Time Machine back up disk.

You should see the Utilities Menu where you can use Disk Utility and Erase the disk/media not any of the volumes underneath (e.g. erase Apple SSD AP0256J Media). Format it and name it Mac OS SSD or whatever you want.

Last, exit Disk Utility and select Restore System from Time Machine Back up. This will, again, erase Mac OS SSD and restore everything including the Recovery HD to Mac OS SSD. I have done this many times without issue and my system is back to having everything (OS, user accounts, data, settings) without reinstalling any apps or reconfiguring anything.

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Answer 3

Govindadas Author

Level 1

15 points

Mar 1, 2018 8:10 AM in response to keg55

Thanks kegg55,

Will definitely try this once I get some free time, as at the moment I am completely running out of time, and my free space on hard drive. :-)

In the meantime, is there a way to format this partition of 50 GB without touching partition of 200 and data on it? I don't mind having two separate partitions until I can use whole 250 GBs.

Thanks in advance.

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Answer 4

keg55

Level 6

11,743 points

Mar 1, 2018 8:17 AM in response to Govindadas

It appears from your screenshot that the 50GB is part of the 200GB and the only available area is the small slice to the left of the 50GB.

What does Terminal - diskutil list show? Can you provide a screenshot of that?

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Answer 5

keg55

Level 6

11,743 points

Mar 1, 2018 8:34 AM in response to Govindadas

I see why now. That 50GB volume is formatted as APFS and you're using Sierra's Disk Utility which does not support APFS. So, you need to use a High Sierra USB thumb drive installer or a clone of High Sierra or something that has High Sierra on it so you can boot from it and use HS's Disk Utility to format it back to HFS+ so Sierra can see it.

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Answer 6

Govindadas Author

Level 1

15 points

Mar 1, 2018 8:32 AM in response to keg55

MacBook has 250 GB SSD. 200 is formated and I am using it, 50 GB is just being wasted because I can't format it. Here is the screen shot from Terminal.