I have an external HD with a bootable version of my macOS 10.8.5 system. I recently updated to macOS 10.11.6 and with Disk Utility I wanted to add a partition to my external drive to have a separate backup disk for the updated OS.

I exactly followed the steps described in "Add a volume to a device without erasing existing data" from Disk Utility for Mac: Partition a physical disk using Disk Utility but something went wrong and now I have three volumes which are all empty.

Doing a recovery program that doesn't return file names and folder structure is useless. I suspect that I need to restore my old partition, how to best go about this? Do I need to write a new partition table with gpt? And how large should this single partition be? If I use gpt show I get:

~$ sudo gpt -r -vvv show disk2
gpt show: disk2: mediasize=1000204886016; sectorsize=512; blocks=1953525168
gpt show: disk2: PMBR at sector 0
gpt show: disk2: Pri GPT at sector 1
gpt show: disk2: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: disk2: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=409640, size=1122168048
gpt show: disk2: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=1122839832, size=823034432
gpt show: disk2: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=1946136408, size=7126576
gpt show: disk2: Sec GPT at sector 1953525167
       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  1122168048      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1122577688      262144         
  1122839832   823034432      3  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1945874264      262144         
  1946136408     7126576      4  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1953262984      262151         
  1953525135          32         Sec GPT table
  1953525167           1         Sec GPT header

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