I’ve just had the uncool job of recovering, or rescuing if you will, my external USB HDD. It’s a mess, Google is completely overrun by companies selling solutions for $39.95. Gah! This is my blow in the fight against this development, I hope it will help some poor soul one day.
The reason for the troubles in my case is a faulty USB controller in the machine I’m using at work, from time to time it will write corrupt data. This time I was unfortunate enough to get the meta data corrupted, call it master boot record, partition table, whatever. In any case no operating system was able to recognize one of the two partitions on my drive. So the search for a solution began and would not bear fruit until I started adding words like “Linux” and “Ubuntu” to “HDD recovery”.
Eventually I ended up in some forum where a guy described how he had fixed an accidentally formatted drive with a free data recovery tool called TestDisk. I would link to the discussion if I could find it again, easier said than done with all the noise polluting this “business”. Anyway I downloaded the windows version and fired it up. After doing the first search pass it found my unbroken partition, nothing special about that I suppose. At that point I was able to choose some kind of advanced search alternative which resulted in finding the missing partition.
Since the corrupt partition was now visible I was able to work with it inside TestDisk, choosing boot and then something like “rebuild boot sector” repaired the whole thing. From what I can remember from the discussion in that forum the same procedure applies to an accidentally reformatted drive, everything except the last boot stuff. I think it’s enough with just having the software find the files again during the second deep search.
Let’s pretend you’ve got a corrupt main drive containing your OS then? If you don’t want to boot properly from another drive with the original as a slave or something you could try a Live CD like Knoppix. Knoppix contains TestDisk and many more recovery tools you can use. If all else fails you could connect a really big USB drive and have TestDisk backup your corrupt drive in the form of the “create image” alternative, your whole original drive has to be able to fit on whatever other drive you want to back it up to.
Update: I just used TestDisk’s sister PhotoRec to recover a bunch of pictures on a broken XD memory card. I simply ran the executable and it found the card automatically. After that I followed the wizard without having to choose any special alternatives, and voila! I got the pictures back.