I have 2 new Samsung 4TB SSDs. I am trying to format them as APFS as for me speed is of upmost importance. When I do so, initially everything seems fine, however after ejecting the drive it will never remount. If I try to mount it from disk utility I get a 49218 error, and if I try first aid it just fails.

If I reformat the same drive as Mac OS Extended everything works fine.

I have tried this on both my new drives with the same results on both, so it is unlikely to be a corrupted disk.

I am running Ventura on a 2019 MacBook Pro (Intel).

Any ideas welcome!

  • 1
    How exactly are you formatting? Right from the lowest level of the device itself or from the volume level? macOS annoyingly hides the device layer by default [press Cmd/2 in Disk Utility to see the device layer], meaning you'd be trying to add an APFS container & partition on top of a pre-formatted MBR device, rather than GUID.
    – Tetsujin
    Commented Sep 5, 2023 at 10:51
  • Hi @Tetsujin - Thank you, and yes I had already read about that issue and made sure I was formatting from the top layer. When I erase and format from the top level (in my case this is called SABRENT Media - despite the fact it is a Samsung disk!) It has the type Disk and partition map is set to GUID Partition map, after formatting it creates 2 layers below this, the first is a container disk of type APFS Container, and below that my volume of type APFS Volume.
    – paul frith
    Commented Sep 11, 2023 at 8:35
  • I'd be very tempted to just send them back. Apart from the anything else, Sabrent are a rival to Samsung, so there's no way you'd ever find one where the other should be, officially. It makes me smell a rat somewhere.
    – Tetsujin
    Commented Sep 11, 2023 at 10:03
  • 1
    Just to follow up - I have sent the drives back, however I should point out that the Sabrent bit was a red herring - it turns out that the drive caddies I was using were Sabrent, whilst the drives themselves were Samsung - hence I believe why I was seeing the Sabrent name appear. I'll post back here once I've received new drives and have checked if the problem persists.
    – paul frith
    Commented Oct 13, 2023 at 16:36


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