I messed this whole thing up in the course of manually removing a boot camp install. I then removed OSX while in recovery mode (yeah...). Disk Utility will not allow me to recover 750gb of free space. The Disk Utility GUI--whether in OSX or in recovery mode--will not allow me to delete the free space it sees.

I reinstalled OSX through internet recovery, but it is stuck on a 248gb partition. I believe that is disk0s2 in the below:

When I open terminal and run

diskutil list

this is what I see:

    /dev/disk0 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         1.0 TB     disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         248.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +248.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Untitled                11.4 GB    disk1s1
   2:                APFS Volume Preboot                 45.6 MB    disk1s2
   3:                APFS Volume Recovery                1.0 GB     disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4

I'm having a terrible time finding a command to nuke the whole thing and start over. I'd really appreciate the help recovering all my missing free space.

Also, FWIW, I have no idea what /dev/disk1(synthesized) is, but maybe it's left over from my boot camp, in which case I'd like to get all of that free space back too. There's no need to preserve data.

thanks all!

  • 1
    Try sudo diskutil apfs resizeContainer disk0s2 0 – David Anderson Jul 27 '18 at 10:04
  • Thank you! That grew my container. Now First Aid gives a warning if “overwllocatjon detected in main device” — is there just a way to start completely over from absolute scratch? And remove all the other stuff showing up in the list? – hegemon Jul 27 '18 at 10:15
  1. Boot to internet recovery.
  2. Open the Terminal application.
  3. Enter the following command.

    diskutil erasedisk apfs "Macintosh HD" gpt disk0
  4. Quit the Terminal application.

  5. Install macOS.


The synthesized drive disk1 is just the physical partition disk0s2 which resides on your 1 TB physical drive (disk0). This disk0s2 partition contains the volumes disk1s1, disk1s2, disk1s3 and disk1s4.

  • Thank you. It is almost 4am here and I am starting to lose it. heh... – hegemon Jul 27 '18 at 10:48
  • The times all depends on where you are on this spinning globe. For me it is almost 6 AM. – David Anderson Jul 27 '18 at 10:50
  • 1
    I just did this and it worked and it “feels” cleaner than just resizing the container as you suggested above. So now I am reinstalling macOS. If you don’t mind and if you know, it would help me understand what is going on to know why there are 20-some disk images showing up in recovery mode when you run diskutil list. It is almost like it is “firmware” saved on the SSD? If you mount and Google the contents of the last disk it seems to be related to the T2 proc. Laptop is new and just want this set up right again. I shouldn’t have messed with it on day 1... thanks again. – hegemon Jul 27 '18 at 10:59
  • 1
    When booting to Recovery, many small temporary drives are created in the Mac's volatile RAM memory. I do not know the reason Apple choose many small drives instead of a single large RAM drive. In your case, you could have just entered the command diskutil list disk0. This command would have omitted these other temporary drives. – David Anderson Jul 27 '18 at 11:14
  • Ah ok. Thank you again for your help. I am a reasonably competent windows person and have been learning FreeBSD lately, but some of the unix/mac idiosyncraxiss still throws me for a loop. Have a good day! – hegemon Jul 27 '18 at 11:23

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