A client has a MacBook Pro Retina with a FileVault2 encrypted boot drive, and the Mac used to dual boot with Linux. Disk Utility apparently showed 4 partitions [Mac HD, Linux, and other 2 small partitions, likely used by Linux as it too was full disk encrypted.
He managed somehow to delete one of the small partitions, and now all disk utility shows are disk0s1, disk0s2, and so on, without even the containing physical drive above in the list.
The os was 12.12.4 [likely, definitely 12.12.x].
This is an image from Recovery > Disk Utility:
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 813902408 2 GPT part - FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF
814312048 1269536 3 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
815581584 1648
815583232 80498047 4 GPT part - 0FC63DAF-8483-4772-8E79-3D69D8477DE4
896081279 641
896081920 2244608 5 GPT part - 48465300-0000-11AA-AA11-00306543ECAC
898326528 262144
898588672 78516224 6 GPT part - 0FC63DAF-8483-4772-8E79-3D69D8477DE4
977104896 131
977105027 32 Sec GPT table
977105059 1 Sec GPT header
Of course he doesn't have a backup. He has the recovery key for FileVault2. Any ideas?
Best Answer
The partition map seems valid and no important small partition has been deleted (maybe one less important EFI or Apple_Boot partition between partition 5 and 6 - the other gaps of unallocated disk space are too small to contain a useful partition e.g. 1648 blocks = ~844 kB).
Partition 2 and 3 of disk0 got the wrong partition type though - the encrypted partition/data shouldn't be lost. Partition 3 has the typical size of a pre-APFS recovery partition (1269536 blocks) and partition 2 probably is the FV2 partition. The proper type of a recovery partition is 426F6F74-0000-11AA-AA11-00306543ECAC and the proper type of a CoreStorage partition (the base of FV2) is 53746F72-6167-11AA-AA11-00306543ECAC (instead of FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF).
Boot to Internet Recovery Mode or another external boot drive and modify the partition types with gpt.
Get the details:
Below I assume the internal 500 GB SSD has the device identifier disk0
Remove partition 2 and 3:
Re-add partition 2 and 3 with proper types:
If not unlock the FV2 volume with:
Verify disk and volume