You can usually convert an HFS+ drive to APFS without erasing its files by using Disk Utility’s Convert to APFS command. However, the option is not available for every drive or partition. Before converting, make a current backup, disconnect unnecessary storage devices, and make sure the drive is not encrypted or formatted in a way macOS cannot convert directly.
Quick Answer
- Back up the drive before changing its file system.
- Open Disk Utility and choose View > Show All Devices.
- Select the HFS+ volume—not the physical drive or an unrelated partition.
- Choose Edit > Convert to APFS, if the command is available.
- Confirm the conversion and wait for Disk Utility to finish.
- Check that the files are present and safely eject the drive.
The conversion is intended to preserve the existing files, but it is not risk-free. A power failure, damaged file system, failing drive, or incorrect selection can cause data loss.
What HFS+ and APFS Mean
HFS+, also called Mac OS Extended, is an older file system used by many Macs and external drives. APFS, or Apple File System, is Apple’s newer file system and is designed for modern macOS storage.
APFS can be useful for drives used primarily with current Macs. It supports features such as snapshots, space sharing, and strong encryption integration. It is generally a poor choice if the drive must also work with older Macs, Windows PCs, game consoles, cameras, or other devices that do not support APFS.
Converting a volume changes how the drive organizes its files. It does not normally delete the files, unlike formatting or erasing. Even so, conversion is a structural change, so a backup is essential.
Before You Convert the Drive
Confirm that APFS is appropriate
APFS is usually suitable for a drive that will be used only with Macs that support it. Do not convert the drive if you regularly need to use it with:
- Windows computers without additional software
- Older Macs
- Smart TVs, cameras, routers, or game consoles
- Devices that specifically require Mac OS Extended or another format
If cross-platform compatibility matters, keep the drive in its current format or consider a format supported by all of your devices.
Back up the files
Copy the drive’s important files to another drive or a backup service before starting. A conversion is designed to preserve data, but it cannot protect files from a failing disk, an interrupted operation, or an existing file-system problem.
Do not treat the conversion itself as a backup. You should have at least one separate copy of anything you cannot replace.
Check the drive’s condition
If the drive is disconnecting unexpectedly, making unusual noises, reporting errors, or taking an unusually long time to open folders, do not begin a conversion. Copy the data to a healthy drive first.
You can use Disk Utility’s First Aid feature to check the volume. First Aid is not a substitute for a backup and may not repair serious hardware problems.
Close apps that use the drive
Close documents, media libraries, virtual machines, backup tools, and any other apps that are reading from or writing to the drive. Make sure file-copy operations have finished.
Warning: The conversion may unmount or temporarily interrupt access to the volume. Unsaved work in an app using the drive could be lost.
Method 1: Convert HFS+ to APFS in Disk Utility
Disk Utility is the safest standard method when macOS offers the conversion command.
1. Open Disk Utility
Open Disk Utility from Applications > Utilities, or use Spotlight to search for it.
In Disk Utility, choose View > Show All Devices. This displays the physical drive, its partitions or containers, and individual volumes in the sidebar.
2. Select the correct HFS+ volume
Find the volume you want to convert. It may have a custom name, such as “Macintosh HD,” “Archive,” or “Backup.”
Select the volume whose format is Mac OS Extended (Journaled), Mac OS Extended (Case-sensitive, Journaled), or another HFS+ variation. You can see the format in the information area of the Disk Utility window.
Be careful not to select:
- The physical drive at the top of the hierarchy
- A different partition
- A backup volume that is currently being used
- A disk containing a system volume you did not intend to change
If you are unsure which item contains your files, use the sidebar hierarchy and select the volume with the drive’s actual data.
3. Look for the conversion command
With the HFS+ volume selected, choose Edit > Convert to APFS.
You may also see a context-menu option after Control-clicking the volume. The exact menu presentation can vary.
If Convert to APFS is unavailable, do not erase the drive just to make the option appear. Review the limitations in the troubleshooting section below.
4. Confirm the conversion
Read the confirmation prompt carefully. Confirm that the selected volume is the one you backed up and intended to change.
Click Convert or the equivalent confirmation button shown by Disk Utility. The wording may vary depending on the macOS release.
Allow Disk Utility to complete the operation. Do not disconnect the drive, shut down the Mac, or force-quit Disk Utility while the conversion is in progress.
Warning: Interrupting a storage operation can make the volume inaccessible or corrupt its file system. If the drive is external, keep its cable connected and make sure its power supply is stable.
5. Verify the result
When Disk Utility finishes:
- Select the converted volume.
- Confirm that its format is listed as APFS.
- Open the volume in Finder.
- Check several folders and open a few important files.
- Confirm that the expected amount of free space is available.
If the volume does not appear in Finder immediately, select it in Disk Utility and click Mount, if that option is available. Do not repeatedly unplug and reconnect the drive while Disk Utility is still updating its status.
What to Do If “Convert to APFS” Is Missing
Disk Utility only shows the conversion command when the selected volume and its current structure support it. Common reasons include the following.
You selected the physical disk or a container
The conversion command may apply only to a volume, not the device listed above it. Select the indented HFS+ volume that contains the files.
The drive uses an unsupported partition layout
Some partition schemes or unusual disk layouts cannot be converted in place. Disk Utility may require the volume to be erased and reformatted instead.
Erasing is a different process: it removes the existing data. Do not proceed unless you have a verified backup and are intentionally rebuilding the drive.
The volume is encrypted or managed by other software
Third-party encryption, backup utilities, security software, or special storage drivers can prevent conversion. Follow the software vendor’s instructions before changing the format.
If you are considering encryption after conversion, review the implications first. You can also learn how to encrypt an external drive on a Mac.
The volume is a startup or system volume
A Mac may not allow an active startup volume to be converted while the operating system is running from it. The process can also differ for older system installations, recovery volumes, or dual-boot configurations.
Do not attempt to convert a system-related volume unless you have a full backup and understand which volume contains the operating system.
The drive has file-system errors
Run First Aid on the volume. If First Aid reports errors it cannot repair, copy your data to another drive before attempting further changes. Converting a damaged volume can make recovery more difficult.
The drive is not actually HFS+
A volume formatted as exFAT, FAT32, NTFS, or another file system cannot be converted to APFS through the HFS+ conversion command. Changing those formats normally requires copying the data elsewhere, erasing the drive, and restoring the files.
Method 2: Copy, Erase, and Reformat
If in-place conversion is unavailable or you want a clean APFS structure, use the backup-and-restore method. This is more broadly applicable, but it erases the drive.
Warning: Erasing permanently removes the drive’s existing data. Verify your backup before continuing.
- Copy all important files to another drive or backup location.
- Open Disk Utility and choose View > Show All Devices.
- Select the physical drive you intend to erase.
- Click Erase.
- Enter a name for the drive.
- Choose APFS as the format.
- Choose an appropriate scheme, usually GUID Partition Map for a Mac-only drive.
- Click Erase and wait for the process to finish.
- Copy your files back to the newly formatted drive.
- Open several files to confirm the restore worked.
This method can also be useful when you want to change the partition layout, remove old partitions, or start with a clean volume. If you need multiple partitions, plan the layout before erasing; learn how to partition an external drive on a Mac first.
Troubleshooting After Conversion
The files do not appear
Check that the APFS volume is mounted in Disk Utility. If it is mounted but missing from Finder, open Finder settings and confirm that external disks are allowed to appear in the appropriate Finder locations.
Avoid writing new data until you know the volume is working correctly.
The drive appears read-only
A read-only volume may indicate permissions, encryption, a file-system problem, or a hardware issue. Run First Aid and check whether the drive is unlocked. If you still cannot write to it, copy accessible files to another location before continuing.
The conversion failed
Record the exact error message. Do not repeatedly retry the conversion if the drive is showing errors or disconnecting. Run First Aid, check the drive’s cable and power, and make sure you have a current backup.
If the volume is still accessible, copy the files to another drive. You can then erase and reformat the original drive if necessary.
The drive disconnects during the process
For an external drive, connect it directly to the Mac rather than through an unreliable hub. Use the drive’s original power adapter when applicable, and replace a damaged cable.
If the drive disconnects more than once, stop using it for conversion and prioritize data recovery.
You need to inspect the APFS structure
APFS can contain containers and multiple volumes, which may not look like a traditional partition layout. Disk Utility can display this hierarchy, while Terminal provides more detailed information. For a command-line inspection, see how to check APFS containers and volumes in Terminal on a Mac.
Frequently Asked Questions
Can I convert HFS+ to APFS without losing files?
Usually, yes, when Disk Utility provides Convert to APFS for the selected volume. Nevertheless, back up the drive first because conversion can fail or expose existing disk problems.
Does converting HFS+ to APFS delete the drive?
An in-place conversion is intended to preserve the files. Erasing and reformatting the drive is different and deletes its existing data.
Will APFS work on Windows?
Windows does not normally provide built-in APFS support. Additional software may be required, and compatibility can vary. Keep the drive in a cross-platform format if you need regular Windows access.
Can I convert a Time Machine drive?
Do not assume that a backup drive can be converted safely just because it uses HFS+. Confirm how the drive is being used, maintain another complete backup, and follow the requirements of the macOS version and backup setup involved.
Should I convert every external drive to APFS?
No. APFS is best for drives used primarily with compatible Macs. A drive shared with Windows PCs, older Macs, or other devices may be better left in its current format.
Can I undo the conversion?
There is no general one-click reversal from APFS to HFS+. To switch back, copy the data elsewhere, erase the drive, format it as HFS+, and restore the files.
Final Thoughts
The simplest non-destructive approach is to select the correct HFS+ volume in Disk Utility and use Edit > Convert to APFS. Back up first, confirm that APFS fits your devices and workflow, and verify the files after conversion. If the command is unavailable, do not force the change—use a verified backup and the erase-and-restore method instead.