This past week, I’ve had the fortunate(?) chance to try out some data recovery software on a malfunctioning hard drive. My MacBook Pro took a beating during transport and the hard drive performance started deteriorating until it would load no more.
At first, it was taking a whole minute to load anything after I clicked anywhere on any application. So I restarted the computer to find that it would not load beyond the Snow Leopard “Universe” background (no login window). Then after the second restart, It would not load beyond the “grey apple with wheel” screen. “Oh oh”, I thought, “my last back up was two months ago… and it was only the work files”. My personal music, photos, and my tax return was not backed up.
As a self proclaimed “Unlicensed Mac Genius”, I knew I had a serious problem on my hands. I’ve had my share of hard drive crashes and was the family advocate for frequent backups. Ironically, I’ve failed to plug in the external drive set up for TimeMachine because my office got displaced after moving out of our old building two months ago.
One thing I wasn’t sure at this point was if the OS was not loading because of a hardware issue or some kind of data I/O issue on the hard drive. I knew I would need a new internal drive any way, so I took the MacBook Pro to the GeniusBar at my local AppleStore retail location.
After listening to the symptoms, the Apple Genius started the machine in verbose mode. Sure enough, the kernel was spitting out I/O errors from disk0 and would not mount it — therefore, would not load the OS. Because Apple does not do data recovery, they were just going to swap out the internal hard drive and give me the old one back for me to try recovering data myself or by sending it to a data recovery company like Drive Savers. I’ve used Drive Savers before, and I knew that they wouldn’t be able to do anything if the head crashed onto the platter.
Two days later, the MacBook Pro came back with a new internal hard drive and the bad drive in a anti-static bag. I tilted the drive back and forth but did not hear anything. All the internal parts must be intact or if they were broken, they were stuck to the magnetized servos. The only way to find out was to plug it in and see what comes out.
For this, I purchased the USB 3.0 Universal Drive Adapter from Newer Technology. I’ve utilized the USB 2.0 version for mobile trouble shooting for a while but I’ve given it away in Japan after the March 11th Disaster. Instead of putting the drive in a real enclosure, I opted to put it on a first aid ice pack with a piece of Tyvek sandwiched between them. The gel filled ice pack would act as a vibration dampener and cooling mechanism. Too McGuyver for you?
After plugging all the cables in, I plugged the USB cable into the computer. The HDD powered up and I could here a slight seeking sound that the head made. “OK, the hardware is intact”, I thought… but the disk did not mount onto the Desktop. I opened up /Utility/Disk Utility to see if the computer even recognized the connection. Well, it did.
The USB connector showed up as the physical device and a single partition volume was contained within. But that partition did not show if it was a Mac/Windows/Unix format or any other status indicator except that it was a 490GB partition. I went ahead and opened /Utilities/Terminal and tried to mount it from the command line. mount told me that there was a “BAD SUPER BLOCK”. Ah…
A Super Block is a marker block on the beginning of the partition that tells modern systems what kind of formatting was used on the hard drive. Without this information, the OS could not tell that the partition was a HFS partition for a Mac. Thus, it wouldn’t even attempt to mount the disk in case it might accidentally write erroneously to it.
If the partition won’t mount and the HFS map cannot be mapped out, any tool that came with the Mac wouldn’t be able to fix it. I had an old copy of DiskWarrior by Alsoft which I could download the updater for, but DW does not work with HDDs that won’t mount. So I did some searching on the Internet and found a software called DataRescue by Prosoft. DataRescue was also available as a downloadable package and what’s more, there was a trial version…