Solution to Fix “Invalid B-tree Node Size Error” on Mac System

Summary: The Invalid B-tree node size error may trigger because of file system corruption, virus infection, bad sectors, or any other problems with the internal hard disk or external drive (if connected). When this error occurs on your Mac, it would freeze, won’t load the OS upon rebooting, and prevent you from working or accessing the drive if the drive is external.  So, if we’re able to fix disk-related issues, we should be able to get rid of this error.



Customer Querry: “I am getting an error message ‘Invalid B-tree node size. The volume could not be verified completely’ on my Mac. How can I fix this?”

Fix ‘Invalid B-tree Node Size Error’ on Mac?

Mac systems have built-in utilities that we can use to check and fix drive-related issues. We’d use these utilities to repair the faulty disk which would eventually fix the error.

FIX 1: Use Disk Utility

This is a GUI-based utility on Mac that can find and repair errors related to the formatting and directory structure of Mac-supported disks.

To fix the error on disk, follow the steps given below:

  1. Connect the drive (if external) to your Mac system
  2. Reboot or Turn on your Mac, and immediately press and hold Command (⌘) and R keys simultaneously

[IMPORTANT]: If the affected drive is an external drive and you’re able to boot your Mac normally, open Disk Utility from the utility folder of your Applications folder, and skip steps 2 through 5.

4. As soon as you see the Apple logo, spinning globe, or other startup screens, release the keys

5. If prompted, enter the requested password and click Continue

6. Select Disk Utility and click Continue. This would open Disk Utility window

  1. From the menu bar or toolbar in Disk Utility Choose View > Show All Devices

On the sidebar, you’d be able to see all the disks with their respective containers and volumes on them.

  1. Follow the below hierarchy (bottom to top) for repairing:

Repair volumes, then containers, then disk

  1. On the affected disk choose the last volume in the hierarchy, select the First Aid button, and click Run to begin checking the selected volume for errors and fix errors

[NOTE]: If you see a Repair Disk button instead of Run, click on it to start repairing.

  1. Moving up in the hierarchy, choose the next volume and repair it the same way as instructed in the previous step
  2. Following the same sequence, repair all the other volumes
  3. Once all the volumes are repaired, repair the next items (if available) – which could be containers – above volumes
  4. After sequentially repairing the containers, choose and repair the disk itself.
  1. Once the repairing process is complete, restart your Mac (if the drive is internal), or disconnect and reconnect the drive (if external) and see if the error is fixed

If you still see this error, follow the next method.

FIX 2: Run FSCK Command

FSCK is a command-line utility to fix internal or external disk errors such as ‘Invalid B-tree’ on Mac. You can run this command only by rebooting your Mac into Single User mode. Let’s see the steps.

2a. Run FSCK Command on Mac Boot Drive

  1. Restart your Mac, and press Command+S keys while it restarts

You’d enter Single User mode.

  1. Release the keys when you see white text start appearing on the screen
  2. When the white text has completely loaded you should be able to see a command prompt at the bottom of the screen that reads root#.

If you don’t see root# at the bottom, hit Return once or twice. Doing this would show root#.

  1. Type the command /sbin/fsck –fy and then press Return to fix the error on Mac boot drive

Where, -fy means force (f) check file system, and automatically say yes (y) to any prompt.

  1. After execution of the command completes, try restarting your Mac by typing reboot and hitting Return key
  2. Check if this boots your Mac and gets you rid of the error on Mac

2b. Run FSCK Command on Mac External Drive

If you see this error when you connect your external drive and couldn’t access it due to this error, you can run fsck command by including the File System and disk identifier or Device Identifier of the external drive in the command.

In the steps below, we’ll first find the Device Identifier and File System on disk which could be HFS+, APFS, etc. After getting this information, we’d be good to run fsck command.

  1. With the external drive connected to your Mac, open Terminal (/Applications/Utilities/
  2. Type diskutil list command on the terminal window and hit Return

This will open the command-line version of Disk Utility which shows a list of all the connected drives with respective volumes on them.

Invalid B-tree Node Size Error

  1. Locate the affected external disk on which you want to run fsck command, and find its Device Identifier and File System. Device Identifier looks like /dev/disk1 and the File System may look like HFS, APFS, etc.
    Invalid B-tree Node Size Error
  1. Note down the File System and Disk Identifier. This information would be required when we’d run FSCK command on the external disk
  2. Enter Single User mode by restarting your Mac and immediately pressing Command+S keys together
  3. On the command prompt that opens, run FSCK command using the following syntax:

/sbin/fsck_<File System> -fy <Disk Identifier>

For example, if the File System you noted is HFS and Disk Identifier is /dev/disk1, the complete command would be:

/sbin/fsck_hfs -fy /dev/disk1

Once you’ve typed the command in accordance with the File System and Disk Identifier, you need to hit the Return key.

Invalid B-tree Node Size Error

  1. After the command has finished executing, disconnect your external drive and connect it back to see if the error is fixed

If you’re unable to fix the error by using FSCK command, you’d need to format the disk that throws the ‘Invalid B-tree node size’ error on Mac. But because formatting would delete all the data stored on disk, recover your crucial data by using a data recovery tool like Stellar Data Recovery for Mac.

Stellar’s Mac data recovery software is a safe and globally trusted DIY data recovery tool. It can effectively recover data from severely corrupted, malware-infected, and error-throwing drives on Mac.


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