I have an external hard drive with two partitions. One partition was used to save files and the other was dedicated to Time Machine. Now I have a new hard drive which I use exclusively for Time Machine, so in the first hard drive I simply want to delete the Time Machine partition and merge its empty space in the other partition.

The problem is that using Disk Utility I was able to delete the content in the Time Machine partition, but I can't merge it. The minus sign which I would normally use to remove a partition is greyed out and there's a message saying "You can not remove the first volume on the disk".

I read that using diskutil from the command line might work, but I'm not sure how to do it. This is the diskutil output:

~ ❯❯❯ diskutil list disk2
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS Time machine backup     750.0 GB   disk2s2
   3:                  Apple_HFS Files                   1.2 TB     disk2s3
  • Try this command in Terminal: sudo diskutil mergePartitions JHFS+ Files disk2s3 disk2s2 I'm assuming two things: 1) your data is backed up and 2) you want to keep the "Files" 1.2TB partition.
    – Allan
    Commented Dec 27, 2018 at 13:19
  • @Allan you're correct about 2, but the data on the "Files" partition are not backed up. Is there a high risk of losing them?
    – Carlo
    Commented Dec 27, 2018 at 16:14
  • You're attempting to change the partition table of a drive that contains what I presume to be important files. Things fail, typos can happen and the fact that you're getting advice from someone across the Internet, which by definition means, can't see the whole picture and put hands on, (honest) mistakes can be made. I do this all the time and I make sure I have a backup even when doing trivial changes like this.
    – Allan
    Commented Dec 27, 2018 at 16:17

1 Answer 1


Try First Aid button on Disk Utility. See what will came up. Maybe this way the app recovers / fixes all of your HHD issues. Then try to erase (once more ) and merge your disk. In many cases First Aid is a necessary step in order to get your job done. Cheers.

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