Merging APFS Containers using the Disk Utility Application

Question

I recently deleted my dual boot from my mac, but I am now left with two partitions that I can't figure out how to merge. I would like it to be normal again with just one container: Macintosh HD. I'm running MacOS Mojave.

Here is my current situation as shown in the "Disk Utility" application and the output from the diskutil list command.

Answer 1

The Disk Utility application probably can not be use to fix your Mac. Below is a alternate procedure.

1. Start up the Mac from macOS Recovery over the Internet by restarting and immediately pressing and holding the the key combination Option-⌘-R.
2. From the menu bar, select to open a Terminal application window.

3. Enter the following command to get the GUID Partition Table (GPT) entries.

   gpt -r show disk0
   

   An example output is shown below.

   $ gpt -r show disk0
         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   97656248      2  GPT part - FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF
      98065888        544         
      98066432   97245184      3  GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC
     195311616        891         
     195312507         32         Sec GPT table
     195312539          1         Sec GPT header
   

4. Enter the command given below to change the GPT.

   gpt -f remove -i 3 disk0
   gpt -f remove -i 2 disk0
   gpt -f add -i 2 -b  <start> -s <size> -t apfs disk0
   

   Where <start> and <size> are integers taken from the row with index equal to 2 in the table shown in step 2. An example is shown below.

   $ gpt -f remove -i 3 disk0
   disk0s3 removed
   $ gpt -f remove -i 2 disk0
   disk0s2 removed
   $ gpt -f add -i 2 -b  409640 -s 97656248 -t apfs disk0  
   disk0s2 added
   

   You will need to replace 409640 and 97656248 with the values shown in your GPT table.

5. Restart the Mac back to macOS Mojave.

6. Enter the command given below in a Terminal application window to reclaim the free space.

   sudo diskutil apfs resizeContainer disk0s2 0
   

Answer 2

If you wish to do this in the GUI, you can do advanced hard disk editing with Paragon Hard Disk Manager. Not "merge" merging the containers, but most likely you'll need to remove a containter and then resize main container where the macOS resides. It can be done on the fly - i.e. you can edit the same partition/container from which you booted the system. Paragon Hard Disk Manager has 10 day trial period, during which you can use all its functions.