Massive disk corruption and data management

by postbreak

I have experienced just about every disk corruption known to OSX and the feeling of despair never seems to go away. Just today I had the dreaded “Invalid B Tree node size” error which means my drive was disconnected before it was unmounted forcing it to write garbage to an important spot on the disk. I have had worse however. Everything from needing to sector edit to regain control to shredding the disk only to cancel so I could format. I have learned a few tricks that might help you before you decide to reformat and lose all your data for good.

How much is your data worth? If you had a drive fail chances are you can get your data back, the only thing limiting you is the amount of money you have in your pocket. Professional data restoration is generally out of reach for normal users and thousands of dollars and hour. We’re left with few options. 

The best way to restore your data is to have a back up. It’s a no brainer however hard drives are getting larger and larger. Backing up your photos is easy, backing up 400GB’s of your movies on the other hand can get costly. That exact scenario is what put me in between a rock and a hard place. I didn’t think to backup my backup.


There are many tools out for Mac users to take advantage of but I am going to list the three big ones that helped save my important data from certain destruction. I am in no way paid by these developers so don’t worry, money doesn’t back this list. Click the icons to go to the developer’s website.


Disk Warrior

Disk Warrior

Disk Warrior was able to repair my “Invalid B Tree” error in about 15 minutes which is pretty fast for all 400GB’s of data I could have lost. This is the go to application when you’ve lost all hope. Is $99 worth your data? Well for me it was money well spent. Some of my files that were restored included homework, TV recordings that came off of VHS tapes, and even a few family trips to the zoo that are irreplaceable. 

Disk Warrior costs $99 and if you own a previous version you can upgrade for $49.



Drive Genius

Drive Genius

Drive Genius is the application I use when I need to get down and dirty with partitioning a disk. You can do everything from defragment to sector edit as well as advanced formating and repairing. Drive Genius was unable to fix my B Tree problem however I don’t believe that’s what this application is made for. If you need to mess around with advanced features of a disk such as defragmenting and repartitioning on the fly, then this is your application. 

Drive Genius runs $99.


Techtool Pro

Techtool Pro

Techtool Pro is the application you can get from Apple with your applecare subscription. If that says anything about the application then you know it’s a powerhouse. I personally don’t use Techtool Pro however some of my other Mac friends swear by it. Costing just about the same as the rest of utilities ($98) I wouldn’t be surprised if it contained the same utilities. Techtool stands out in that it doesn’t just revolve around disk utilities and it can test other hardware as well. 

Techtool Pro costs $98.


Out of all the tools I mention I strongly suggest picking up Disk Warrior. A lot of the specialty disk tools in Drive Genius can be performed by the command line for power users however for the average Mac user that might be a bit too risky. So while I wait for my 354GB of data to copy to my backup drive I hope you never have to resort to one of these applications but like a good locksmith, always have one in your pocket or phone.