Recently, Apple introduced its new file system called APFS (Apple File System). This brand new file system is designed for use on SSD disks, but there’s nothing wrong with using it on usual hard disks.

Today I bought a brand new external hard drive (disk) Transcend StoreJet 25M3 1Tb. A Transcend company says that it can be used on both Windows and macOS. But most WD drives come formatted in the NTFS file system format for OS Windows, while for macOS we needed the HFS+ format or the Apple’s brand new APFS (Apple File System) format. macOS can read but not write to NTFS formatted drives. So the only workaround is to format the disc to HFS+ or APFS.

The easiest way to format the disc is by using macOS built-in Disk Utility app. I started up the Disk Utility and tried to Erase the disc and make it HFS+, then convert it to APFS. But after I get HFS+ I noticed that the “Convert to APFS…” item is for some reason deactivated. It is visible but it is gray and can not be selected.

What causes this issue

After research, I came to the conclusion that this could happen after updating macOS to version 10.13.3 as before there was no such a problem.

This is not a Transcend issue. It can happen with a disc from any manufacturer. But this is not a problem with the disc at all. It’s all about the brand new APFS file system.

What I have:

How to solve it

To solve this issue, we will use the Terminal app and the two tools diskutil and dd. Both tools are built-in in macOS, so we do not need to download or install anything. First, we format the disk in the HFS+ in the Terminal app, and then convert the HFS+ into APFS using the Disk Utility app.

Note! APFS requires macOS High Sierra. Earlier versions of the Mac operating system don’t mount APFS-formatted volumes.

Open Terminal app.

Firstly we need to find the proper system name of our disk (hard drive):

diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS Container disk1         121.1 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +121.1 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            105.5 GB   disk1s1
   2:                APFS Volume Preboot                 21.0 MB    disk1s2
   3:                APFS Volume Recovery                509.9 MB   disk1s3
   4:                APFS Volume VM                      3.2 GB     disk1s4

/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk2
   1:                  Apple_HFS Transcend               1.0 TB     disk2s1

There are two types of devices (methods to communicate with devices):

  • raw devices /dev/rdisk*, communication is direct with the disk.
  • buffered devices /dev/disk*, data transit via buffer.

When using dd or other duplication programs, always use raw device.

The below commands assume this is disk2, but replace disk2 with the correct disk if it’s something different.

Before any operations on the disk we must unmount it:

diskutil unmountDisk force disk2
Forced unmount of all volumes on disk2 was successful

Note! Do not forget to replace the disk2 before pressing the Enter.

Now we will write zeros to the disk (this will erase the entire disk):

sudo dd if=/dev/zero of=/dev/rdisk2 bs=1024 count=1024

Note! Do not forget to replace the rdisk2 before pressing the Enter.

Enter your computer password after prompted and then watch the magic happen…

1024+0 records in
1024+0 records out
1048576 bytes transferred in 2.448794 secs (428201 bytes/sec)

Let’s now try to partition the disk. This will be the HFS+ format:

diskutil partitionDisk disk2 GPT JHFS+ "Transcend" 0g
Started partitioning on disk2
Unmounting disk
Creating the partition map
Waiting for partitions to activate
Formatting disk2s2 as Mac OS Extended (Journaled) with name Transcend
Initialized /dev/rdisk2s2 as a 931 GB case-insensitive HFS Plus volume with a 81920k journal
Mounting disk
Finished partitioning on disk2
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:                  Apple_HFS Transcend               999.9 GB   disk2s2

Note! Replace “Transcend” with the name that you want to give to your hard drive.

Note! Do not forget to replace the disk2 before pressing the Enter.

Looks good. Our Transcend hard drive prepared for the APFS file system.

Finally, we can use the Disk Utility app to convert our hard drive from HFS+ format to APFS format.


If this article helped you solve the problem then please leave a comment. :smiley:

Thanks for reading!

Arthur Gareginyan

Arthur Gareginyan

Arthur is a designer and full stack software engineer. He is the founder of the studio SpaceX-Chimp and the blog His personal website can be found at

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