Mac – Disk Utility “restore from” list does not include any volumes

Just let it sit - I have the same EXACT situation and while I was researching online, it just "popped up" and was available. It seemed like my good computer was trying to fix the bad computer first, before it mounted as ext hd.

Hope this helps.

I think Disk Utility misses a proper EFI partition at the beginning of the disk.

If you don't want to completely erase the drive you should be successful following the steps below:

• Open Terminal and enter the following to get an overview:

  diskutil list
  

  The 3 TB disk is your external disk. In the next steps I assume the disk identifier of your external disk is disk1

• Get the block size of the external disk:

  diskutil info disk1 | grep "Device Block Size"
  

  In the next steps I assume that the Device Block Size is 512 bytes. If you get another block size (i.e. 4096 bytes) leave a comment.

• Get the partition table of the external disk:

  sudo gpt -r show /dev/disk1
  

  The result is similar to the output below (your sizes are different though):

         start        size  index  contents
             0           1         PMBR
             1           1         Pri GPT header
             2          32         Pri GPT table
            34      262144      1  GPT part - E3C9E316-0B5C-4DB8-817D-F92DF00215AE
        262178        2014         
        264192  2244603904      2  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
    2244868096  2048002015         
    4292870111          32         Sec GPT table
    4292870143           1         Sec GPT header
  

• Unmount the external disk:

  diskutil umountDisk /dev/disk1
  

• Now add a third partition with

  sudo gpt add -b 2244870110 -i 3 -s 1000000000 -t 48465300-0000-11AA-AA11-00306543ECAC disk1
  

  I left some unallocated space (2014 blocks) between partition 2 and 3.

  The resulting partition table looks like this then:

         start        size  index  contents
             0           1         PMBR
             1           1         Pri GPT header
             2          32         Pri GPT table
            34      262144      1  GPT part - E3C9E316-0B5C-4DB8-817D-F92DF00215AE
        262178        2014         
        264192  2244603904      2  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
    2244868096        2014         
    2244870110  1000000000      3  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
    3244870110  1048000001         
    4292870111          32         Sec GPT table
    4292870143           1         Sec GPT header
  

  You should choose a bigger size than 1000000000 blocks. The number of blocks has to be dividable through 8. The max size in my case would have been 2048000000 (1000000000 + 1048000001).

• Now format the new partition with a file system and name the volume (in the example below Backup):

  sudo newfs_hfs -J -v "Backup" /dev/disk1s3
  

• Mount the volume and verify it:

  diskutil mount /dev/disk1s3
  diskutil verifyVolume /dev/disk1s3