1

I can't find a disk to select to install OS X in Internet Recovery Mode. Also I can not erase the disk or partition. I gave all the details.

Two days ago I decided to do a clean wipe on my MacBook Pro with factory SSD and Mountain Lion. I not able to reinstall the fresh OS X Mountain Lion from Internet recovery because the drive to select wont show up when you have to pick where to install the OS X in Disk Utility. If I try to erase the original disk start up it just hangs and says it's partitioning. I gave a detailed description from start to now on what is happening can anyone help? I believe it has to be fixed some how in terminal.

First I went into my local recovery of High Sierra and did an erase of the disk.

Then I did an Internet Recovery and erased the disk0s2 partition. (Everything went good) After that I did an erase for the main disk start up 500.28 GB Apple SSD SD512E Media. (Which got stuck or my internet crashed) I quit disk utility.

Then I got back in Internet Recovery and again I tried to erase the disk start up 500.28 GB Apple SSD SD512E Media. (This time on the bottom right corner where it shows a progress bar it starts out with and stays in Partitioning. Estimated time less than 1 minute but it never progresses and the time keeps growing I tried leaving it for over 12 hours and a few other attempts no luck).

I checked my system with the quick AHT and everything is fine got no issues. Did the test a few times.

I think I will have to do something in terminal. I believe the drives are getting confused with some sort of formatting issues. Below I have stated what exactly happens and all the options I have available in Disk Utility.

When I restart and go into internet recovery mode. disk0s2 partition always comes back but is grayed out. If I click on it all buttons are grayed out as well cant do anything other than erase. When I erase it I get this error: Volume Erase Failed. Volume Erase failed with error: MediaKit reports bad partition or no map found.

After trying to Erase disk0s2 partition if I try to erase the main disk start up 500.28 GB Apple SSD SD512E Media I always get the same issue where in the right bottom corner it shows the progress that it is Partitioning. Estimated time less....and the time keeps climbing slowly till it hangs.

Now after if I have attempted to erase the main disk 500.28 GB Apple SSD SD512E Media. Things change than they are at first from without having any erase attempts. After the attempts the fix buttons get grayed out with the 500.28 GB Apple SSD SD512E Media. Before any erase attempts on partition tab on main disk I am able to verify disk it says everything is good and partition is ok. When I try to click repair disk it says Error: Couldn't repair the partition map...EFI system partition could not be created. I can open the partition tab and see disk0s2 but everything is grayed out but keeping in mind if I try to erase the disk0s2 or 500.28 GB Apple SSD SD512E Media the partition tab becomes empty where I can created another partition but it never happens and gets stuck in the progress bar in the right corner says waiting for partition to reappear.

This is what 500.28 GB Apple SSD SD512E Media bottom before I try to erase. Do remember that under this disk its the partition disk0s2 which is grayed out but if I try to erase it disappears unless I restart and get back into Internet Recovery.

Disk Description : APPLE SSD SD512E Media Total Capacity : 500.28 GB (500,277,790,720 Bytes) Connection Bus : SATA Write Status : Read/Write Type and Location : Solid State Disk, Internal S.M.A.R.T. Status : Verified Partition Map Scheme : GUID Partition Table

500.28 GB Apple SSD SD512E Media bottom after I try to erase. You can see how the Partition Map Scheme chages but this is after I try to erase and cancle where it gets stuck in Partitioning. Estimated....time.

Disk Description : APPLE SSD SD512E Media Total Capacity : 500.28 GB (500,277,790,720 Bytes) Connection Bus : SATA Write Status : Read/Write Type and Location : Solid State Disk, Internal S.M.A.R.T. Status : Verified Partition Map Scheme : Unformatted

All I need is help on how to get a disk to pick out to put Mountain Lion on. Right now it shows nothing and the install button is grayed out. Does it have something to with the sizes of the partitions not matching up to the total amount I have available?

This is what diskutil list looks like. I am not very tech-savvy but this is all the information I can offer. I don't understand why I have so many partitions when in Disk Utility all I see is 500.28 GB Apple SSD SD512E Media and under it disk0s2 which is grayed out.

-bash-3.2# diskutil list

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2: 7C3457EF-0000-11AA-AA11-00306543ECAC               500.1 GB   disk0s2

/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     Apple_partition_scheme                        *1.2 GB     disk1
   1:        Apple_partition_map                         30.7 KB    disk1s1
   2:                  Apple_HFS Mac OS X Base System    1.2 GB     disk1s2

/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk2

/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk3

/dev/disk4
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk4

/dev/disk5
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk5

/dev/disk6
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk6

/dev/disk7
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *6.3 MB     disk7

/dev/disk8
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *2.1 MB     disk8

/dev/disk9
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *1.0 MB     disk9

/dev/disk10
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk10

/dev/disk11
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *524.3 KB   disk11

/dev/disk12
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               *1.0 MB     disk12
2

While upgrading to High Sierra the main partition of an SSD (disk0s2) is converted to APFS - Apple's new file system introduced 2016 in Sierra.

Older system versions like Mountain Lion don't contain APFS drivers and neither diskutil nor Disk Utility can handle the partition type of file system properly. In Internet Recover Mode (depends on the key combination) you are probably booted to a Mountain Lion base system.

There are several methods to remove the "unknown" partition.

One is outlined below:

  • In Internet Recovery Mode open Terminal: menubar > Utilities
  • Enter diskutil list to get the details

    Usually the internal disk has the device node disk0. All other disks are either external disks or related to Internet Recovery Mode (disk1-disk12 in your example)

  • If external disks are attached (probably all disks larger than 2 GB - including thumb drives, but don't unmount/eject your internal disk), unmount, eject and detach them:

    diskutil umountDisk diskX
    diskutil eject diskX
    
  • Remove the APFS container partition and EFI:

    gpt destroy /dev/disk0
    
  • Create a new partition table:

    gpt create -f /dev/disk0
    exit
    
  • Exit Terminal and open Disk Utility in the Utilities window
  • Partition and format the disk as needed

    1. In the left pane choose the 500 GB drive at the top
    2. Hit the "Partition..." tab in the larger right pane
    3. Choose "1 Partition" in the partition layout drop-down menu
    4. Choose a name
    5. Choose Mac OS Extended (journaled) as format
    6. Hit apply
  • Nothing happened though Klanomath I still cant partition with disk utility and disk0s2 still remains grayed out and same as before. When I ran diskutil list command it gave me the same exact list as it was before. – MacGuy Jan 20 '18 at 2:30
  • if I try to delete the grayed out disk0s2 and go back into terminal and run a disk list this is what shows. -bash-3.2# diskutil list /dev/disk0 #: TYPE NAME SIZE IDENTIFIER 0: *500.3 GB disk0 – MacGuy Jan 20 '18 at 2:45
  • The rest look the same as on top. Sorry I cant fit it all in here. /dev/disk1 #: TYPE NAME SIZE IDENTIFIER 0: Apple_partition_scheme *1.2 GB disk1 1: Apple_partition_map 30.7 KB disk1s1 2: Apple_HFS Mac OS X Base System 1.2 GB disk1s2 – MacGuy Jan 20 '18 at 2:45
  • I dont have any external drives. I do have another Mac Air Book could that help? – MacGuy Jan 20 '18 at 2:46
  • I bought it at the same time and believe it came with the same exact OsX just that the specs are differnt. I am checking to see if my neighbor has a Thunderbolt cable or can a usb be used. Are we going to just back up from another device? – MacGuy Jan 20 '18 at 2:50

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .