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Data recovery from flash drives is problematic enough, but recovering encrypted data from a failing flash drive might be nearly impossible.č
Truecrypt Issue: I cannot read disk even though I successfully mounted Windows 7 Professional, Truecrypt 7.0a
Following your recommendation, I decided to use Truecrypt to encrypt a SD card that contains personal data to keep it off the work laptop. This has worked very successfully for about three months until this morning. When I entered the password to mount the volume, it mounted as usual with no error messages. However, when I tried to access the mounted drive (volume), it said, You need to format the disk in drive Z: before you can use it. Do you want to format it? Of course, I clicked No.
I consulted the Truecrypt user manual that said that I should restore the volume header. As recommended, I dismounted the volume, then used Tools > Restore volume header using the Restore the volume header from the backup embedded in the volume option, and the normal password worked. I got the message saying the volume header was successfully restored. However,, the same problem persists, "You need to format the disk....." as above.
This is a real disaster for me, I need the drive contents. Do you have any idea what to do next?
I do not.
I may have one straw to grasp at, but overall, I'm concerned that this situation cannot be recovered.
I'll explain why I think that is and what I would have done differently.
I'll also ask my readers for any additional ideas.
This ends up catching people by surprise, and unfortunately, it does so fairly often.
How quickly it wears out depends on the quality of the device and how much it's written to. (Writing causes wear, reading does not.)
My suspicion is that your SD card, which uses flash memory, has likely worn out.
That would explain why the device can be mounted (the area with the TrueCrypt header has not worn out), and yet appears unformatted to Windows (the area with the file listing probably has).
Start by write protecting the card.
SD cards have a small slide-switch that prevents writing to the device, which in turn prevents any recovery attempts from making the situation worse (a common mistake).
Now, try a file recovery tool, perhaps Recuva, on the mounted volume and see if it "sees" anything that it can recover.
It's a long shot, but you have nothing to lose by trying.
If your data exists in only one place, it's not backed up.
I don't see this as an issue of encryption as much as it is an issue of keeping critical data in only one place. Encrypted or not, had that one place been, say, a portable hard drive that died in some unrecoverable way, you'd be in the same position.
There are two approaches that would have lessened the impact of this device failure:
Backup the TrueCrypt volume. Simply making a copy of the TrueCrypt volume somewhere else on a regular basis quickly, and safely, backs up everything in it. Lose the original and you can simply copy and mount the backup.
Backup the contents of the TrueCrypt volume. If done properly, backing up the unencrypted contents of the volume can protect you from both device failure and encryption failures, such as forgetting the pass phrase. The "trick", if you want to call it that, is that, by definition, this is sensitive data so you'll want to make sure that it's protected some other way - most often using physical security that involves some form of physical lock or perhaps some other form of secure access control.
As you might guess, I do both.
I do want to be clear and point out that TrueCrypt doesn't seem to be at fault here. Even if the data were unencrypted on the device, a device failure could still have rendered it completely and irrevocably unrecoverable.
Encryption can make data recovery more difficult and often impossible, but backing up makes data recovery unnecessary.
I'd be interested in hearing from readers about what other recovery options might apply in this situation. Aside from tools like Recuva, it's certainly possible that there are other approaches that are worth investigating. Please share your thoughts in the comments below.
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