Many web pages claim that when you install 10.13 on an SSD, you have an option to convert to APFS. Many others claim that when you install 10.13 on an SSD, you will be converted to APFS whether you want it or not.

Neither was the case for me. I have an internal SSD that upgraded to 10.13 and continued to the current 10.13.6. Default disk utility knows it is SSD and HFS+ but will not convert it. Recovery partition won't convert it either. And in none of my upgrades was I ever offered the choice.

I don't want to erase and do a multi-hour install, then have to do a multi-hour restore from backup. Especially since I recently did (10.13.6) from recovery partition and it did not convert.

One page said you can't do it on your boot volume till 2017. But 2017 is long gone.

SSD was in this refurb when I bought it from the Boston Apple store January 2017. I used Migration to put apps and accounts on it, Software Update since then. Never used FileVault nor RAID nor Bootcamp.

UPDATE: As detailed in the question and the "half-answer," there was never an automatic update nor an offer to do so nor were any of my attempts to get around it successful as of August 2018.  I gave up on the idea at that point. However, I noticed in disk utility today (13 Aug 2019) that my boot SSD is now APFS. I have no idea when Apple did the conversion without asking, but it was after the updates to 10.13.0 through 10.13.6. Now I have 10.14.6

Configuration info (when the question was asked—before the surprise conversion):

MBP-WWG:Desktop Admin$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage ISSD                    1.0 TB     disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS ISSD                   +1.0 TB     disk1
                                 Logical Volume on disk0s2

MBP-WWG:Desktop Admin$ 

About Finder Drive Volume

  • I've never been given the option; it just did it without asking, twice. Once even after I'd manually converted it back to HFS. This was with an old Mac Pro 5,1 & an aftermarket SSD.
    – Tetsujin
    Aug 7, 2018 at 6:53
  • Can you share more about your disk setup? (screenshots from DiskUtility for example) ... Are you using RAID? CoreStorage? FileVault 1/2? etc
    – jksoegaard
    Aug 7, 2018 at 9:31
  • Try running “diskutil cs list” In terminal, and attach a screenshot of the result
    – Harcker
    Aug 7, 2018 at 12:49
  • @Harcker better copy and paste the text output of the command (as the OP did) rather than a screen shot
    – mmmmmm
    Aug 7, 2018 at 13:00
  • @Harcker: It just says HFS, like everything else I already posted.
    – WGroleau
    Aug 7, 2018 at 13:18

2 Answers 2


Well, I have the beginning of an answer:

MBP-WWG:~ Admin$ apropos apfs
APFSUserAgent(8)         - APFS new container observer
apfs.util(8)             - APFS file system utility
apfs_hfs_convert(8) !!!! - convert an existing HFS file system to APFS file system
fsck_apfs(8)             - APFS consistency check
mount_apfs(8)            - mount an APFS volume
newfs_apfs(8)            - construct a new APFS volume
MBP-WWG:~ Admin$ man 8 apfs_hfs_convert

But the challenge is when the Terminal is open in recovery mode, how many environment variables do I have to set to make it actually work? I know it comes up with PATH=/usr/bin:/bin:/usr/sbin:/sbin but none of those directories exist in recovery mode (they're all on the main volume). I don't know whether redefining PATH is sufficient. Some commands may need other environment variables to function. (shared libraries, manpath,

Tempted to try it on the old machine that has a spinner instead of an SSD.

  • What if you install High Sierra on an empty external volume, boot from that, launch Disk Utility, click the eject button next to your internal boot volume's icon, select your internal boot volume's grayed out icon and choose Convert to APFS from the Edit menu?
    – Trellis
    Aug 8, 2018 at 7:29
  • Don’t have one big enough. I did, however, create a bootable installer. When that is booted, the convert executable on the internal drive can be invoked—and says “device busy”. And of course, if unmounted, “no such path.” Next experiment: copy the executable into the installer before booting it: (Afterward, “read-only filesystem”)
    – WGroleau
    Aug 8, 2018 at 11:46
  • 1
    Try unmounting it then using Terminal to remount it non-read-only (/sbin/mount -uw /). Then unmount and try.
    – Trellis
    Aug 8, 2018 at 13:31
  • 1
    Can’t unmount the volume you booted from.
    – WGroleau
    Aug 9, 2018 at 14:49
  • Assuming you're still booted from the bootable installer.
    – Trellis
    Aug 9, 2018 at 15:01

It is possible from recovery mode and/or usb setup. Start the mac in recovery mode (hold cmd+R at boot). Open disk utility, select volume from the left click Edit and convert to APFS. If option is greyed out unmount the volume first from the toolbar.

  • Since it has already been converted by one of the many updates since asked, I can’t test this now. However, in the original question, I clearly stated that the recovery partition will NOT do it.
    – WGroleau
    Feb 19, 2020 at 15:12

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