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

Posted by Katrina to Mac Data Recovery on January 25th, 2018

Today, I plugged my 1.5 TB HFS external hard drive into my Mac Pro and received an error message saying "The disk is unreadable by this computer". I tried to verify the external hard drive with Disk Utility and I got the message: "Invalid B-tree node size. This disk needs to be repaired". What does invalid B-tree node size mean? How do I get it solved and recover data from invalid B-tree node size external hard drive on Mac?

What is invalid B-tree node size error?

Whenever you save a file on Mac, the Mac operating system creates a unique entry for the file on the index table with B-tree format. So each time you access a file, the Mac operating system navigates this tree to locate the file. Once B-tree is corrupted, the Mac operating system fail to and you will see the error message: "Invalid B-tree node size. This disk needs to be repaired".

What cause invalid B-tree node size error?

Invalid B-tree node size error happens on Mac due to broken B-tree structure, file system corruption, catalog node files damage, virus attack, abrupt system shutdown, head file corruption, operating system malfunctioning, boot sector error, etc.

How to fix invalid B-tree node size error without losing data?

Invalid B-tree node size error will result in Mac computer crash, unbootable hard drive and data inaccessibility, so it is important to resolve this problem as soon as possible.

Solution 1: Fix invalid B-tree node size error with fsck Command

The fsck command is used to repair disk and file system problems on your macOS.

Step 1: Start your Mac in single-user mode. Restart it, and then press and hold the Command+S keys while it boots.

Step 2: Type the command /sbin/fsck -fy into the terminal and press Enter to start a file system check.

Step 3: When the fsck command has your disk checked and repaired, type reboot and press Enter. Your Mac will reboot and return to the usual login screen.

Solution 2: Fix invalid B-tree node size error by reformatting

Reformatting is always the last choice we make as it will erase all data on the hard drive completely. But don't worry! we can recover data before reformatting. Here we recommend you a free Mac data recovery software - iBoysoft Mac Data Recovery.

Step 1: Recover data from invalid B-tree node size hard drive, then perform reformatting

iBoysoft Mac Data Recovery is a free data recovery software that can recover data from invalid B-tree node size hard drive, recover data from unreadable hard drive, recover data from unrecognized hard drive, recover data from corrupted hard drive, recover data from unmountable hard drive, recover data from inaccessible hard drive, recover data from uninitialized hard drive, etc. on macOS Mojave 10.14/High Sierra 10.13/10.12 Sierra/10.11/10.10/10.9/10.8/10.7.

That's not the end, iBoysoft Mac Data Recovery is the best APFS data recovery software that can recover lost data from encrypted APFS volume, recover data from formatted APFS drive, recover data from unmountable APFS drive, recover data from unreadable APFS drive, recover data from corrupted APFS drive, recover data from inaccessible APFS drive, recover deleted/lost APFS partition, etc.

Tutorial to recover data from invalid B-tree node size hard drive with iBoysoft Mac Data Recovery

1. Launch iBoysoft Mac Data Recovery.

2. Select the hard drive which has invalid B-tree node size error and click "Next" to start scanning.

Recover data after invalid B-tree node size error

3. Preview scanning results, choose files we need, and click "Recover" to recover files.

Step 2: Fix invalid B-tree node size error by reformatting

After getting lost files back, we can fix the corrupted hard drive by reformatting it.

1. Launch Disk Utility.

2. Select the corrupted hard drive on the left part of the window.

3. Click Erase on the top of the window.

4. Complete related information (name, format, scheme), then click Erase.

Still have questions?