Since the release of macOS 10.13 (High Sierra) in 2017, Apple has preferred to use its own development “Apple File System” (APFS) for SSDs, hard drives and image files. This proprietary drive format offers a number of advantages over its predecessor HFS+. Reading, writing and creating new drives and images in the legacy format has continued to be possible for the past nine years. A “deprecation” in the notes on macOS 27 (Golden Gate) now signals the end – a good time for long-time Mac users to take stock and think about a change. What is HFS+?
HFS stands for “Hierarchical File System”, the appended plus indicates that it is the newer iteration – from 1998. However, Mac users rarely see this name in this form. When you call up Disk Utility to format a drive or create an image file, macOS calls this format “macOS Extended”. Under macOS 26 (Tahoe), creating an encrypted image file in the “macOS Extended (journaled)” drive format is still possible (although not advisable).
HFS+ is called “macOS Extended” in Disk Utility.
Inventory and exchange
The format an image file uses is only revealed after it has been activated, which you can do by double-clicking on the file. For encrypted drives you have to enter the corresponding password. Then select the mounted volume in the Finder sidebar and choose Get Info from the File menu (+I). The inspector reveals under “Format” whether HFS+ or APFS was used. Similar to SSDs and USB sticks, reformatting an image is not possible without losing the content. Instead, create a new APFS image in Disk Utility and copy the files from the soon-to-be-outdated image into it.
The information dialog reveals the drive format – but only if the image file is activated (mounted).
Special case Time Machine
Some long-time Mac users may not even know that they use HFS+ on a daily basis. This is the case if you have been using the same (encrypted) Time Machine backup for a long time. Up to macOS 10.15 (Catalina), all backups were set up using HFS+ by default. It was published seven years ago. A simple rule of thumb: Time Machine backups from Apple Silicon Macs are most likely already created as APFS. Intel Macs are worth checking. To do this, open the (network) volume in Finder and activate the file stored there with the ending “sparsebundle”. To do this, you must enter the password for the Time Machine encryption. To check the format, proceed as with image files: +I opens the inspector, which reveals the format.
This Time Machine backup already uses APFS.
With Time Machine, only setting it up helps
Even with Apple’s built-in data backup mechanism, you can’t simply flip a switch to change the format. Instead, set up a new backup in Settings/General/Time Machine by clicking on the plus symbol. For external drives, make sure it’s formatted in APFS in advance using Disk Utility – otherwise macOS 11 or later won’t accept it as a backup destination. For NAS drives backed up via SMB, a drive image is automatically created in APFS format.
There is still time left
Deprecation means that there is still some time left until the format is changed. At least macOS 27 (Golden Gate) will be able to open encrypted HFS+ images and view their contents. From macOS 28 onwards it will probably be over. In this case, it is worth continuing to use older (Intel) hardware or setting up a virtual machine (VM) with macOS 27.
