I have the same problem even after Deep Scan. Despite Recuva stating "Comment: No overwritten clusters detected," when opening any recovered .doc files with MS Word 2007, this error is displayed:
Microsoft Office Word needs a converter to display this file correctly. This feature is not currently installed. Would you like to install it now?
Similarly, opening recovered .xls files returns:
The file you are trying to open, <filename>, is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted source before opening the file. Do you want to open the file now?
I've not found a single recovered file that I can open. If there are "no overwritten clusters" and Recuva does not alter the recovered data, how is it that the files are corrupted?