When I ran Smart PC Solutions' Smart Data Recovery on my hard drive it found well over 30,000 deleted files before I stopped its run. That seems impressive but the reality was less so. On attempting to access these files, after having restored them to a folder, only the dot txt files were readable. The rest were not. For example, myriad image files were unreadable by image processing software such as PhotoShop.
My hard drive has been de-fragmented several times and hence the space occupied by deleted files over-written. Also many deleted files would be for tidbits of temporary data and hence unwanted anyway.
To give the product another chance, I scanned a 250MB USB thumb drive, which contained a single small (16KB) text file, thinking there would have been less file activity. Thirty four deleted files were found. Actually finding them took an age as scanning the USB drive's free space was slow. They were recovered and then I checked access to them. Text files were ok. A Windows document was gibberish as was an HTML file. A Quark file could not be opened. Image files could not be seen. A PowerPoint file could not be opened, nor an Excel spreadsheet.
Hmm, maybe it's version one trouble.