I was wondering why my drive wasn’t converted to APFS after installing macOS High Sierra public beta.

I tried to convert it to APFS after the fact, by booting into Recovery Mode and opening Disk Utility, but it won’t let me. The option to convert to APFS is grayed out. Is there any way I can convert my drive to APFS?

I also tried to format my external hard drives as APFS. I was able to do that only ONCE. When I tried to do it on my second external hard drive, APFS wasn’t even offered. Does anyone know why I can’t format my second hard drive as APFS?

  • Have you asked Apple ?? - APFS is still in beta, so don’t expect that everything is working yet, and that all drive types are supported. Aug 4, 2017 at 20:36
  • only submitted to feedback assistant because it is in beta ... i do not know where to ask on the apple beta trial issues ... i searched the web and understood it could be done in the disk utility ... but mine is dimmed and not able to pick....
    – cwong668
    Aug 4, 2017 at 23:19
  • This just happened to me as well. The only thing I can think of is that the Macintosh HD is not OEM. The original drive had to be replaced. But I don't see why that would make a difference. steve taffee Aug 5, 2017 at 2:39
  • You should be able to give feedback to Apple on: beta.apple.com/sp/betaprogram Aug 5, 2017 at 13:16
  • beta.apple.com/sp/betaprogram this link is the feedback assistant...
    – cwong668
    Aug 5, 2017 at 21:35

2 Answers 2


According to various threads I’ve read, there are a number of factors that may prevent you from converting to APFS:

  • Third-party SSDs are not supported.
  • Rotational hard drives and fusion drives were supported in Developer Preview 1, but support was removed in Developer Preview 2 (Public Beta 1) due to catastrophic failures.
  • FileVault may need to be disabled before the conversion is allowed.
  • External drives may need to be unmounted.
  • apfs format is not supported on mac using hdd drive in the beta 2 ... it means apfs format is not supported on mac using hdd drive in the macOS High Sierra "PUBLIC" beta ... apple is highly promoting apfs format in macOS High Sierra but never tell the users on hardware restrictions ... this is really BAD...
    – cwong668
    Aug 5, 2017 at 21:46
  • 1
    Yes, like most people I would like if Apple could be more transparent in general; at the same time this is a beta, and features will expectedly remain in flux until the final release. Moving forward, Apple’s stated intent is for APFS to totally replace HFS+ on all drive types.
    – user11633
    Aug 5, 2017 at 22:06
  • i understood it is beta and remain in flux ... but it is in public beta 3 if i remembered correct ... it is not in developer beta ... so apple should say what is good and what is bad in public beta ... microsoft windows 10 fast ring preview tells user what is good and what is bad for the release ... i do not think it tells all but at least some ... not like apple nothing is told...
    – cwong668
    Aug 7, 2017 at 19:29

FYI -- in beta 13 (Sept 1) -- HDD-only Macs cannot be converted to APFS. This is a bitch for testing, because as a developer I need to make a bootable 10.13 beta with APFS to test that file system.

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