Mac – How to merge MBR mapped external drive partitions using macOS High Sierra

disk-utilityexternal-diskhigh sierrapartitiontime-machine

Background: I got a new computer recently, a new MacBook Pro running High Sierra. My old computer was a 2011 MacBook Pro, and I used an external drive to back it up with Time Machine. The drive has two partitions, both Mac X Extended (Journaled), and one contains my backups (Mac Daddy) while the other is empty (007). I no longer need two partitions on the drive, and would like to merge them without losing my backups.

Problem: Disk Utility is being less than helpful, as you can see it won't give me an option to do any partitioning on them, and in fact it doesn't even recognize the two partitions as part of the same drive in the sidebar, though under "Device" info it does say they are both "disk2". I've already erased 007 and run First Aid on both just in case, but nothing changed. I imagine I may have to use Terminal, but I don't know how. Any help would be appreciated!

P.S. I know this is similar to other questions, especially this one which never got solved, but I figured I'd redo it with my specific info.

Thanks!

Results of "diskutil list":

/dev/disk0 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         500.3 GB   disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         500.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            57.7 GB    disk1s1
   2:                APFS Volume Preboot                 20.4 MB    disk1s2
   3:                APFS Volume Recovery                509.8 MB   disk1s3
   4:                APFS Volume VM                      2.1 GB     disk1s4

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *2.0 TB     disk2
   1:                  Apple_HFS MAC DADDY               1.5 TB     disk2s1
   2:                  Apple_HFS 007                     499.9 GB   disk2s2

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Best Answer

If you mouse over the grayed out partition button, you see the message "Disks with Master Boot Record partition maps can not be partitioned." Of course, this only applies to the Disk Utility application. The Terminal application command that you need to enter is given below.

diskutil  mergepartitions  free  none  disk2s1  disk2s2

This command will remove 007 and add the space to MY DADDY. The existing files stored in MY DADDY will be preserved.

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