How to fix invalid B-tree node size error on Mac?

I’m getting an ‘invalid B-tree node size’ error on my Mac and can’t access some files. This started happening after a recent macOS update. Has anyone encountered this issue? Any advice on fixing it would be greatly appreciated.

That “invalid B-tree node size” error is definitely a pain. This kind of issue typically points to some sort of disk corruption, and it’s not uncommon for something like this to pop up after a macOS update. Here are a few steps you can try to resolve this:

  1. Start in Recovery Mode:

    • Restart your Mac and hold down Command (⌘) + R before the Apple logo appears. Release when you see the macOS Utilities screen.
  2. Use Disk Utility:

    • Select “Disk Utility” from the macOS Utilities menu.
    • In Disk Utility, select your Macintosh HD in the sidebar and click “First Aid” at the top. This might fix minor issues.
  3. Boot in Single User Mode:

    • Restart your Mac and hold Command (⌘) + S to boot into Single User Mode.
    • When you see white text on a black background, type fsck -fy and press Enter. This will run a file system check (similar to Disk Utility’s First Aid). Once it’s done, type reboot to restart.
  4. Use Third-Party Software:

    • Sometimes standard tools aren’t enough. You can try Disk Drill, which is quite good for these kinds of problems. You can Download Disk Drill from their official website. This tool can recover lost files and repair disk issues effectively.
  5. Backup and Reformat:

    • If the above steps don’t help, it’s a good idea to back up your important files if you still can, via Time Machine or another backup method. Once backed up, you can erase your disk and reinstall macOS.
    • Again, use Disk Utility from the macOS Utilities screen: Select your drive, click “Erase,” and follow the prompts. After erasing, reinstall macOS from the same menu.

Word of caution—don’t rush to the reformatting step if you haven’t exhausted all other options, and definitely make sure your data is backed up before wiping anything.

If anyone else has more tips or has faced this issue recently and resolved it another way, your insights would be helpful. The “invalid B-tree node size” error isn’t necessarily a death sentence for your data, but it is something you want to tackle sooner rather than later.

I’m skeptical about jumping into all these complex steps right away. The “invalid B-tree node size” error is often caused by disk corruption, which the macOS update could’ve exposed, sure. But before diving into Recovery Mode or Single User Mode, you might just try restarting your Mac and zapping the PRAM (hold down Option + Command + P + R) when restarting. This can sometimes clear up weird errors.

DiskWarrior is another software you might consider. I’ve found it to be more reliable than Disk Drill when handling deep disk corruption. Disk Drill is decent for data recovery, but I’m not fully confident in its repair capabilities. Also, it’s not free, and when paying, you probably want the best tool for the job.

Backup everything before any drastic measure—importance can’t be overstated here. Data loss could easily happen with disk errors, and reformatting should always be the last resort.

Don’t get me wrong, Disk Drill has its uses, especially if you need to recover lost files. Just don’t put all your eggs in that basket. Getting a second opinion (like DiskWarrior) could prove beneficial. Pro tip: keep an eye out for macOS updates that might fix this issue without you having to go through extensive troubleshooting.

Jumping right in, looks like you’ve gotten some solid advice already. That “invalid B-tree node size” error isn’t something you want to ignore, but hold off on diving head-first into intense fixes. I’d say first off, restart your Mac and reset the NVRAM/PRAM (hold down Option + Command + P + R during startup) as @codecrafter mentioned. This can occasionally clear out system-level weirdness that creeps in after an update.

If that doesn’t pan out for you, going through the Recovery Mode route is a good next step. But hey, before you go there, another tool you might want to try is DiskWarrior - it’s probably one of the best when it comes to fixing disk directory problems. It’s true that it’s not free, but few things of real value are, right? I’ve had success with DiskWarrior where Disk Utility just didn’t cut it. Still, Disk Drill is good too, especially if you need to recover files, though I’d lean a bit more on DiskWarrior for actual repair capabilities.

Now, if you’re going into Recovery Mode, here’s a quick refresher:

  1. Restart your Mac and hold Command (⌘) + R, release when the macOS Utilities screen shows up.
  2. Choose Disk Utility.
  3. Pick your startup disk, usually labeled “Macintosh HD”, and select First Aid.

But honestly, if Disk Utility shows it can’t repair the disk, don’t despair just yet. Booting into Single User Mode and running fsck -fy can sometimes do the trick for deeper issues.

If none of those sorts it out, another angle is to boot into Target Disk Mode by connecting your Mac to another Mac with a Thunderbolt/FireWire cable, and see if you can salvage the data that way. Basically, you restart your Mac and hold down the T key until you see the Thunderbolt or FireWire icon on the screen. Your Mac acts like an external hard drive at this point – super handy for quick data recovery.

Regarding data backup, totally agree with @techchizkid. Always, always, always back up before doing anything major. Time Machine is the built-in way to go, but if you’ve missed setting that up before this issue, there’s always the manual drag-and-drop to an external drive route. And, if fate has already spirited away some files, Disk Drill can be your ally. Download it here and give it a shot.

Now, if you need to erase and reinstall macOS (holding thumbs you don’t reach this stage), here’s the drill:

  1. Go back to the macOS Utilities in Recovery Mode.
  2. Select Disk Utility and your drive.
  3. Click Erase and follow the on-screen cues - use APFS or Mac OS Extended (Journaled) depending on your macOS version.
  4. Once erased, reinstall macOS from the same menu.

Before jumping into reformatting, consider if any further software can assist. Besides DiskWarrior and Disk Drill, some people swear by Data Rescue - haven’t used it myself but always worth looking into.

Extra tip: Keep an eye on future macOS updates. Sometimes these system-level bugs get patched in updates, and your problem might magically vanish after the next one. But, don’t delay fixes waiting for them if your data is at stake.

In conclusion, stratify your approach: simple reboots and PRAM resets first, move to Recovery and Disk Utility, then consider advanced tools like DiskWarrior or Disk Drill. And before any erasing, a thorough backup is paramount. It’s tempting to rush for a quick fix, but patience and methodical steps often save both time and data in the long run.