Can a Mac OS Extended formatted SSD drive be opened in later macOS versions?

Can a Mac OS Extended formatted SSD drive be opened in later Mac OS'?

In order to update the formatting to (APFS) I assume the drive would be wiped clean. Correct?



  • Apple File System (APFS): The file system used by macOS 10.13 or later.
  • Mac OS Extended: The file system used by macOS 10.12 or earlier.


[Re-Titled by Moderator]

Original Title: Formatting external SSD drives

MacBook Pro 16″, macOS 15.5

Posted on Jul 28, 2025 09:39 AM

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4 replies

Jul 28, 2025 04:42 PM in response to werdup

macOS Extended Journaled was the required format for Mac boot drives up to 10.12. It was also the default format for boot drives in 10.13 & 10.14 if the drive was a traditional HDD.


Apple File System (APFS): The required format for Mac boot drives in macOS 10.15 and later. In macOS 10.13 & 10.14 it was applied by default if the boot drive was an SSD.


All Macs since the advent of OS X can read & write macOS Extended format drives.

Jul 28, 2025 05:34 PM in response to werdup

werdup wrote:

In order to update the formatting to (APFS) I assume the drive would be wiped clean. Correct?

You can convert an HFS+ volume to APFS. Within Disk Utility on one of the menus there is a "Convert to APFS" option when you have an HFS+ volume selected.


Before you attempt the conversion, make sure you have a good backup of the data on that drive just in case something goes wrong.


FYI, if the external drive is a Hard Drive, then it may be best to leave it with HFS+ since APFS tends to cause extra wear on a Hard Drive. If the drive is an SSD, then APFS is fine since APFS is optimized for an SSD.


Can a Mac OS Extended formatted SSD drive be opened in later macOS versions?

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