External APFS Drive?

In a previous article I talked about formatting spinning external USB connected hard drives with the APFS file format. It is doable, but I am finding out it is not so desirable. I describe how to actually do the formatting in my previous article, but I want to describe a not so good side effect.


One of the drives I formatted was my backup drive for my iMac, my main workflow machine. This is a spinning HD in an external USB enclosure. It is not a fast drive, but it is supposed to be super reliable, a good backup drive.

After formatting it to APFS it continued to work, but with this caveat. It took forever to mount on the Desktop. And, my iMac restarts went from about 45 seconds to about 5 minutes. It was like the OS had trouble seeing and mounting the drive. I finally got fed up with this behavior and just erased the drive and formatted it to HFS+, the old Mac file system.

Here is the drive in Disk Utility:

Disk Utility would not let me re-partition the drive, I just had to use the “Erase” command which erased the APFS install and the “Container”, created a 2TB partition and formatted the drive HFS+.

By the way, here is my internal SSD with APFS on it:

Here is what the iMac Backup drive looks like after the formatting:

“Mac OS Extended (Journaled)” means it is formatted to HFS+.

The drive performs normally now. Of course, after erasing the drive I had to setup and run all my backups again with the excellent Get Backup Pro App. Not a big deal as far as I am concerned since everything is now running normally.


If you have formatted an external USB hard drive to APFS and notice it is running slow, you may want to reformat it to HFS+. I am sure the APFS file format may work better on spinning hard drives in the future, but for now, it may not be the way to go.