How to get my hard drive back to original state?

Question

How to get my hard drive back to original state?

I have a 2014 mac mini with 2TB fusion drive.

Well, I did have....

Through a combination of unfortunate events:

1) Regular system crashes

2) Attempting to install Linux in a new partition and then installing reFind

I ended up having to reinstall MacOS from scratch. The issue is, the OS now thinks I only have a 200GB hard drive now, so I reinstalled High Sierra into that. So instead of the OS being in a nice, fast, SSD partition, it's in a much slower SATA hard drive. And yes, it feels so much slower running a Mac from a regular hard drive rather than SSD.

I think the hard drive is fine. I just messed up the partitioning when attempting the Linux dual boot install.

So my question is - how do I get my Mac back to its original state with the full 2TB fusion drive available ? And hence being able to reinstall again but into the SSD ?

I've tried all the normal Mac reboot options, recovery mode, and running disk utility from there. But disk utility just doesn't see the full disk any more, just the 200GB drive.

Is there a different utility I can use to get the hard drive back to what it should be?

Thanks for any help on this 🙂

Mac mini, macOS High Sierra (10.13.3), Late 2014 Model

Posted on Oct 5, 2018 7:15 AM

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Answer 1

dialabrain

Level 10

137,659 points

Oct 5, 2018 7:33 AM in response to sadasdadadasdsa

First, there's no such thing as a "SSD partition". You either have an SSD or a HDD or a Fusion drive which you say you have.

You need to re-fuse your Fusion drive. How to fix a split Fusion Drive - Apple Support

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Answer 2

Nov 6, 2018 9:55 PM in response to sadasdadadasdsa

It's fixed 🙂

After installing OS to the SSD, I just then went into Disk Utility, and erased the 2TB Physical Disk. So I now have a 2TB disk back, yay.

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Answer 3

Nov 6, 2018 8:31 PM in response to sadasdadadasdsa

P.S. Quick update, when I rebooted after that into OSX, it's been a partial success. The 121GB Flash storage has reappeared. That wasn't there before I did the recovery.

But it's the 2TB SATA Disk. It still thinks it's a 199.15 GB drive instead of a 2TB drive. If I could get that back, I would be "good to go"....

Should I try now putting the OS back on the flash drive? Currently it's on the 199.15GB SATA disk.

Just looking in Disk Utility I can see why it only thinks I have a 199.8GB volume. Most of the space is taken by "disk1s2" which is 1.8TB in size, but this doesn't appear as a logical volume. I just see it in the partiton graphic.

So I think my plan is:

a) Reinstall the OS on the 121GB SSD

b) Find a way to "rejoin" the 2TB drive 🙂

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Answer 4

Nov 6, 2018 8:02 PM in response to dialabrain

I got into recovery mode, and then terminal. Saw both disk0 and disk1 as my physical disks. So all good.

When I did "diskutil unmountDisk disk0", it was successful.

But when I did "diskutil unmountDisk disk1", it failed with error:

"Unmount of disk1 failed: at least one volume could not be unmounted. Unmount was dissented by PID 0".

So how can I unmount disk1? What process is using it?

And when I try to do "diskutil cs create Macintosh\ HD disk0 disk1" I just get "Error -69888: Couldn't unmount disk"

So kind of stuck at the moment.

Any help very much appreciated.

Thanks,

Lee

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Answer 5

Oct 5, 2018 7:35 AM in response to dialabrain

thank you so much 🙂

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Answer 6

dialabrain

Level 10

137,659 points

Oct 5, 2018 7:40 AM in response to sadasdadadasdsa

You're welcome.

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Answer 7

BDAqua

Level 10

251,299 points

Nov 6, 2018 11:50 PM in response to sadasdadadasdsa

Good work.

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How to get my hard drive back to original state?

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