Back in August I cloned a 500GB APFS container off a 2TB external HDD consisting of a Time Machine backup of my old macOS install and some APFS scratch space, and formatted that partition on the physical drive. I've DD'd it back, and now the whole partition refuses to mount and Disk Utility doesn't show anything useful.

No, I didn't read even a word of advice on here before I did it. Yes, this is a lesson in looking before you leap. There's no baby pictures or launch codes on there, it'd just really suck to lose some of that stuff. Luckily, OMZ kept my shell history back far enough to check the commands I used to back it up and restore, respectively:

sudo gdd if=/dev/disk5s2 of=/Volumes/New\ York/apfs_container_82123.img status=progress

sudo gdd if=/Volumes/New\ York/apfs_container_82123.img of=/dev/disk5s2 status=progress

As you can see I just kinda sent it with no regard for encryption, block size, snapshots, SIP, or anything like that. "New York" is an EXFAT partition on that same drive of the remaining 1.5 TB that I saved the image to.

As mentioned I made this copy in August, so this would have happened on either macOS Monterey or Ventura. The version of DD I use currently is GNU Coreutils 9.4 gdd from Homebrew. Running head on that file doesn't show anything useful like filesystem information like it would for FAT, though I don't know if that's normal for APFS.

Is there anything I can do about this?

  • 1
    I assume /disk5 as a whole has still the same structure/partitioning as last August? apple.stackexchange.com/questions/296451/… might be wort a try
    – nohillside
    Commented Jan 4 at 11:28
  • I feel dumb enough to delete this question now but I'll leave it up in case it helps anybody else. Yes, that's it. You're a godsend, thank you. Commented Jan 4 at 18:06
  • Thanks for coming back on this! I've closed the question as a duplicate, it's always helpful to have several entry points as people might use different search terms for the same thing.
    – nohillside
    Commented Jan 4 at 18:20

1 Answer 1


As pointed out by nohillside this answer explains how to fix this issue, I hadn't seen it while looking through similar questions.

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