Mixed views on this product.. standard stealth & space defrag options seem to work well but when I tried complete/name option hundreds of files disappeared or couldn’t be accessed on drive tested. I’m no expert but could this have been the MBR being corrupted so it wasn’t pointing to correct file locations any more? Fortunately I had a clean, recent backup so just restored, no long-term harm done. I’ve searched web for anyone else experiencing same without success so maybe this was a one-off or drive had already been corrupted and defrag process just compounded it. Product gets glowing reviews generally.