I posted recently about a new issue with APFS, introduced with macOS High Sierra Public Beta 4 (build 17A315i): after the upgrade procedure, the volume is slightly damaged reporting an 

"fsroot tree invalid" error

in Disk Utilities’ First Aid. Preventing a successful boot into the OS in 4 out of 5 times approximately.

This weekend I had the time to have a closer look at it in order to solve another issue in the course of my struggles with APFS on an external SSD disk. It was an obvious thought to me – as Disk Utility wasn’t able to fix the issue from within Recovery Mode – that erasing the existing APFS volume will most likely be the only fix.

I cannot prove that it is the only way – but completely reformatting the external SSD Disk as APFS did the job!

What I encountered during the solution approach is somehow a bug (or missing/unfinished feature) in the Disk Utility.app. You are not able to directly erase a broken APFS volume or it’s container aka partition – it always fails saying "Unable to erase disk". I had to approach it as follows:

  1. Boot into High Sierra Recovery Mode using CMD+R just after triggering a Mac startup
  2. Start Disk Utility & select the main Drive volume in the Volume list
  3. "Erase" it and choose the old HFS+ format "Mac OS Extended (Journaled)"
  4. When done, select the now HFS+ formatted newly created volume
  5. Go into the "Edit"-menu and choose "Convert to APFS..."
  6. This should succeed successfully – if you do a First Aid check now, you shouldn’t see a "fsroot tree invalid"-error anymore!
  7. Quit Disk Utility & go on reinstalling macOS High Sierra Beta from the Recovery main menu
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4 thoughts on “Solution approach: fixing APFS disk issue “fsroot tree invalid” in macOS High Sierra Public Beta 4 (17A315i)”

  1. Pingback: Overcome macOS High Sierra’s Gray Screen of Death after OS update – Swiss Mac User 

  2. Hi, is it possible that this is still an issue?
    I updated my mac in April to macOs 10.13.4 and had many problems and system freezes on my machine.
    When I was going to the apple store, they suggested that I should do a complete reset and fresh install of macOs (well, I’m working with my machine and since I did that my timemachine backups are not working anymore, had to recover files manually …)
    But even when I did that, my mac keeps doing weird things. Freezing, flickering screen etc. I still have that fsroot tree error when I run fsck.
    I would like to try your solution, but would like to avoid it if possible because of that timemachine problems … 🙁

    Reply

    1. Hi nerdcel,
      Well, the issue & solution approach described in this post has the cause, that you won’t even be able to install neither run macOS High Sierra! So I guess, this is not the problem you are facing…

      I had a few years ago a brand new MacBook Pro, which showed exactly the strange behaviours when using them, as you are describing! My sister bought one of the new MacBook Pro Touchbar models recently – and she also had such issues.

      In our cases, the root cause always seemed to be the Logicboard inside the MBPs: we had them replaced by Appl or the reseller under the regular warranty – afterwards, with a new Logicboard, it felt like a totally different Mac and everything worked smooth and stable again.

      I don’t know what type of Mac you have – but based on my experience it seems to be a real Hardware issue.

      Hope it helps – let me know, if you were able to resolve the issue at some point!
      Oliver

      Reply

    2. Yes, this is still a problem. I have a late 2013 15″ with the same problem. Discovered this because I’d delete files and OSX would not free up the space. Drive filled to 99%.

      Kind of a mess.

      Reply

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