iMac main partition disappeared after deleting a different partition
So, I created a 20GB partition in my iMac to install Ubuntu. That worked fine, but then it turned out I needed a bit more space for the software I wanted to install, so I turned the computer off and rebooted on the main partition (Mac HD, I believe). I then deleted the 20 Gb partition, and I'm sure that's the one I deleted because I triple checked it's size, just in case. Something weird happened right away, the Mac HD partition was now being recognized as an external drive. I didn't think too much of it though, as I was more worried about the fact that those 20GB of space apparently weren't available. I then decided to restart the computer, maybe that would fix the issue. Well, the Linux partition was still there but the Mac HD option was gone -.-
Both regular and Safe boot take me to a grub command line, as well as booting the Linux partition, so it seems I actually erased it. Running diagnostics (Command-R and D keys on startup) tells me everything is fine. I also tried reseting the PRAM, to no effect.
I started the Ubuntu installation process, just to see if it would work, and when choosing where to install it there's an empty 20GB "partition" of free space, which I imagine corresponds to the partition I created and then erased, as well as 230GB partition, of which an 'unknown' amount is used.
Is there any hope of recovering the disk? I don't have a complete backup of the system, only a semi-recent backup of important work. I can live with losing some stuff, but I'd rather try to salvage it if possible, it will be quite a nuisance reinstalling all the software I use on a regular basis. If there's a way, how would I go about it? Also, if you have any idea of what might have caused this, I'd love to know.
Thanks in advance!
EDIT: Since no one has answered I decided to give a blind try at this, let's hope I didn't screw up.
Interestingly, while the first time i used diskutilthe main partition was disk2, it now seems to be disk14. I haven't done anyhing else at this point, is this normal behaviour?
diskutil list
/dev/disk0 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme +2.1 GB disk0
1: Apple_HFS OS X Base System 2.0 GB disk0s1
/dev/disk1 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +5.2 MB disk1
/dev/disk2 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk2
/dev/disk3 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk3
/dev/disk4 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk4
/dev/disk5 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk5
/dev/disk6 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk6
/dev/disk7 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +6.3 MB disk7
/dev/disk8 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +2.1 MB disk8
/dev/disk9 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +1.0 MB disk9
/dev/disk10 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk10
/dev/disk11 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +524.3 KB disk11
/dev/disk12 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +1.0 MB disk12
/dev/disk13 (disk image):
#: TYPE NAME SIZE IDENTIFIER
0: untitled +6.3 MB disk13
/dev/disk14 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *251.0 GB disk14
1: EFI EFI 209.7 MB disk14s1
2: FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF 230.8 GB disk14s2
gpt -r show disk14
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 450721136 2 GPT part - FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF
451130776 39103943
490234719 32 Sec GPT table
490234751 1 Sec GPT header
I haven't got a clue what to look for, but I'm assuming that, since I see non-zeros, this is a CoreStorage partition. Is this correct?
dd if=/dev/disk14s2 count=3 | vis -c
3+0 records in
3+0 records out
1536 bytes transferred in 0.001849 secs (830641 bytes/sec)
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I'm still reticent to proceed, but I'll wait a bit to see if someone is able to respond...
EDIT2: I proceeded with the assumption that I was looking at a CoreStorage partition. When verifying the disk, this was the error message I got:
diskutil verifyVolume disk14s2
Error starting file system verification for disk14s2: The given disk has a storage system (such as AppleRAID) which is not supported for this operation (-69718)
diskutil verifyDisk disk14
Problems were found with the partition map which might prevent booting
Error: -69808: Some information was unavailable during an internal lookup
Should I continue with diskutil repairDisk disk14 or does this error mean something else should be atempted?
EDIT3: According to David Anderson, I was actually looking at a APFS container partition. Following the steps he provided I got this:
gpt -r show disk14
start size index contents
0 1 PMBR
1 1 Pri GPT header
2 32 Pri GPT table
34 6
40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
409640 450721136 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
451130776 39103943
490234719 32 Sec GPT table
490234751 1 Sec GPT header
Disk verification seems to be good now, but verifying the volume still returns an error, albeit a different one.
diskutil verifyDisk disk14
The partition map appears to be OK
diskutil verifyVolume disk14s2
Error starting file system verification for disk14s2: Unrecognized file system (-69846)
Should I try repairing now?
Based on klanomath's answer to the question OS volume shows as type 'FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF', you should proceed as follows.
-
Boot to Internet Recovery Mode (or a third party drive).
-
Open Terminal in the menubar Utilities > Terminal
-
Get an overview with
diskutil list. -
Assuming the disk identifier for the internal drive is still
disk14, then enter the following commands. Otherwise, make the appropriate substitutions for the disk identifier.diskutil umountDisk disk14 gpt remove -i 2 /dev/disk14 gpt add -i 2 -b 409640 -s 450721136 -t 7C3457EF-0000-11AA-AA11-00306543ECAC /dev/disk14
Additional comments on some of your questions.
- What you thought was a CoreStorage partition is actually a Apple File System (APFS) container partition.
- The identifiers (such as
disk0ordisk0s2), used by commands such asdiskutilandgpt, are assigned as needed. In other words, there is not permanent identifier assigned to a disk, partition, container, etc. You may need to view the output fromdiskutil listto see the current identifier assignment.