I was trying to recover some files I'd deleted from my recycle bin in Windows 7, and I found a few which were listed as unrecoverable but which hadn't been over-written. I tried recovering them, and the files were the correct size but were completely blank when I looked at them in Notepad - page after page of spaces.
Just curious: what's going on here? And would there be any way to get data back from those files? I don't need them, but I always thought that deleted files stayed intact until over-written, so I'm interested in knowing what happened.
I don't know all the criteria that Recuva uses to classify the state of deleted files (actually I don't know any, I can only guess). If the clusters the file points to have been overwritten by another file is one. And if the clusters don't have a recognisable or compatible file signature would be another example and would match your case. This can occur when the clusters have been overwritten by another file but then that file has been deleted.
Most deleted files that have an entry in the Master File Table can be recovered, in as much as the clusters the MFT entry points to can be retrieved, even if they are junk from the data point of view. Your file data, having been overwritten, is lost forever.