Mac Data Recovery on Broken File System (Invalid B Tree Node)

Summary: The blog explains the detailed information about ‘Invalid B-tree node error’, identifies the causes of the error and the probable solution.

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Picture this! You open up your MacBook Pro running over the latest macOS and find its battery drained. You next attempt to plug it in and boot up your Mac, but it shows a flashing folder bearing a question mark. However, in a few minutes, the system starts to boot up. To be on the safer side, you then decide to back up the hard drive. Unfortunately, you are not able to do so; and, this time, when you try to start the machine, it does not boot at all. Now, when you tried the internet recovery option to get to the ‘diskutil’, the recovery failed, and you encountered ‘invalid node structure’ and ‘disk full’ message. Furthermore, when you tried resolving this issue via Terminal, the message – ‘Volume was found corrupt and needs to be repaired’ appeared!

The main reason behind the ‘invalid node structure’ error is the incorrect size of B-tree structure or invalid node size of B-tree. It is quite likely that the Mac file system is broken. In this case, running ‘fsck’ in single user mode can help resolve this issue. However, in case any data loss takes place, you can recover your data using a Mac hard drive and data recovery application.

If your Mac hard drive has not been formatted in the last couple of years, this may also have triggered the issue. If the Time Machine backup is available, locate it for Mac data recovery on the broken file system.

Since there was no clicking sound coming out of the system, and the only symptom was that the performance considerably slowed down, then it’s quite probable that the issue must be the broken file system. Now let’s understand the Mac file system corruption.

Introduction to Corrupt File System

File system issues in Mac may be resolved by rebooting the system in the safe mode. The Broken file system is a common issue with Mac machines. To resolve this, reboot the Mac machine while pressing down the Shift key. It will perform a force check and error correction on the file system. Booting the system in the safe mode will delete all the cached files and start the machine in a limited working state with only basic information.

Introduction to Invalid B-tree Node Structure

Invalid B-tree node size implies that the Mac hard drive volume is damaged or has become corrupt. This leads to data inaccessibility. Each individual file on a Mac has a unique entry in the index table with a B-Tree format. Each volume on the hard drive has certain information such as directories, files, directory threads, and file threads associated with the system.

When an attempt to access a file is made, the Operating System parses the B-tree to locate the actual file on the hard drive. When the B-tree becomes corrupt, and the operating system fails to parse it for locating file information, the corresponding error message appears.

Reasons for Invalid B-tree Node Error Message

Several reasons are responsible for Invalid B-tree node size error. They are:

• failure of B-tree structure
• corrupt file system
• corrupt header file
• boot sector error
• missing catalog file
• abrupt system shutdown
• virus or malware attacks
• operating system malfunction

To get rid of this error message, you need to perform an immediate recovery procedure for recovering broken file system as it can cause a situation of permanent data loss.

Fix Invalid B-tree Node Error using Built-in Methods

Below are the built-in methods available for fixing the invalid B-tree Node error:

Fix #1: FSCK Command: Running FSCK command via Terminal can also provide an immediate resolution to the corresponding error message. You may require a sound knowledge of command line interface to execute this command.

Fix #2: Reformat Hard Drive: Reformatting the hard drive could result in resolving the B-tree node size error. As reformatting can cause data loss, it is recommended to backup data before you format the hard drive.

What to do in case of data loss?

In case any data loss occurs while performing either of the above mentioned ‘Invalid B-tree node’ resolutions, you can recover data using Stellar Data Recovery Professional for Mac software.

The software aims at recovering data from Mac hard drive and external storage drives. The software searches for lost volumes from APFS, HFS, HFS+, NTFS, ExFAT, and FAT file systems. Integrated with advanced scan algorithms, it efficiently retrieves deleted as well as formatted data from encrypted hard drives and Time Machine backup drives. All kind of data can be recovered including photos, documents, music files, database files, video files and much more.