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SuaveCrouton Author

Level 1

5 points

My iMac hard drive has been halved

No I'm not going crazy and I understand the difference between used and available space. My iMac 27 5k retina display late 2014 is equipped with a 1 tb fusion drive, 1.12 tb to be exact. Problem is that the actual capacity, the amount of total useable space is only 563.33 GB, I cannot use any more hard drive space outside of that, and I have no partitions currently on said drive.

I speculated that this split might be due to my previous uses of bootcamp but I've removed every single instance of those properly through the bootcamp assistant application, and checking with disk utility I confirm that I have no current partitions on my hard drive. So I'm rather baffled as to why basically half of my hard drive is nowhere to be found. I performed first aid on the hard drive recently to fix a frequent crashing/restarting problem I was having, as well as restarted the computer in OS X recovery mode, if thats of any use, but I think the hard drive problem was in existence before that.

I've provided screenshots below of my dilemma.

iMac (Retina 5K, 27-inch, Late 2014), macOS Sierra (10.12.4), null

Posted on May 15, 2017 6:31 PM

Top-ranking reply

Loner T

Level 9

59,513 points

Posted on May 16, 2017 3:39 PM

Notice the large chunk after GPT3 on disk1. We are going to create a 'fake' GPT entry and make it look like a FAT32 partition, that the BC Assistant can then Remove/Restore. Please post any error messages that you encounter during these steps.

First, we need to disable System Integrity Protection using the following steps.

You have either El Capitan or Sierra. You will need to disable SIP by booting into Local Recovery (using Command+R - not Internet Recovery) and click on Utilities -> Terminal and type

csrutil status

csrutil disable

csrutil status

Boot normally and check the output of csrutil status which should now be disabled.

Second, we will create a new GPT4 using the following steps, after GDisk (aka GPT Fdisk) is installed (do not enter text like this. It is for informational purposes).

sudo gdisk /dev/disk1

x (Experts menu)

l (set sector alignment to... this is lowercase 'L')

1 (... to one sector)

m (Main menu)

n (New)

4 (GPT4)

865634440 (Start sector)

+1087890695 (Size. Notice the '+' sign)

0700 (Microsoft Basic Data)

p (Print the GPT)

w (Write the GPT)

y (Confirm write)

q (quit, if necessary)

Third, we need to repair disk1 so the disk 'knows' that we have a GPT4.

diskutil repairDisk disk1

If everything works correctly, you can now run BC Assistant, and click on Restore/Remove.

Once you get your disk space back, re-enable SIP by using Local Recovery and

csrutil enable

I suggest you back up OS X, before your next adventure in Windows Wonderland.

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21 replies

Drew Reece

Level 6

10,666 points

May 15, 2017 9:37 PM in response to SuaveCrouton

I marked the other as a duplicate & asked for this one to be moved - it generally better to keep the history so users don't get as confused when they mix up the threads.

Hope it all works out…

Loner T

Level 9

59,513 points

May 16, 2017 2:32 PM in response to SuaveCrouton

"Sudo" requires your password, not an Administrative password. If you chose a password when you setup the account originally, that is the password you need to use.