Complicated External HD/Enclosure Problem (MBR/MFT? I Have No Idea)

Hello all, I'm hoping someone can help me with a bit of a confusing problem I'm having with an external drive; at the very least, perhaps they could explain what happened?

I have been running a WD Green 1TB through an Eagle CONSUS SATA to USB enclosure for an external backup solution. No real problems to speak of until recently I had a friend stop by with his sisters' old computer drive so he could pull data from that (by using my enclosure) and putting it on another drive. What happened is as follows:

- removed my 1tb drive from the enclosure
- put his sisters' drive in the enclosure
- drive was not recognized. Rebooted.
- drive was recognized - plugged in his USB 3.0 drive to an additional port, completed the backup.
- plugged my 1TB back in; was not recognized
- rebooted
- 1TB was recognized, but now has the files/folders that were listed on his sisters old drive!! Additionally, the drive letter had changed

I can't understand what has occurred; the drive seems to have taken on the files/folders of his sisters' drive, but the files do not actually exist. I have attempted to recover my old files through various Partition/file recovery software. EaseUS Data Recovery seems to have found the files, but after recovering them (over a near 36 hr timeframe) none of them open properly (.cr2 files - Canon RAW). Luckily this is just a backup drive and almost all of these files are already on a different drive as well; however, I greatly would like to find a way to revert my drive to it's proper (not corrupted?) state, or at least view what was on there to confirm everything is backed up before I'm forced to reformat it.

I am open to suggestions and grateful if anyone can provide insight. Thanks!

Something definitely doesn't add up here. How could any content or directory structure from the laptop end up on your drive if you removed it from the enclosure? It sounds like a detail was left out, like did he attempt to connect your enclosure first, before you removed your drive?

DeaconFrost said:

Something definitely doesn't add up here. How could any content or directory structure from the laptop end up on your drive if you removed it from the enclosure? It sounds like a detail was left out, like did he attempt to connect your enclosure first, before you removed your drive?

This is truly baffling to me as well, but is what has occurred (unless the enclosure somehow applied the file record from the sisters' hard drive to the usual drive). I wish I was leaving something out, some logical reason for this to have happened; unfortunately, this is not the case.