One possibility is that there's corruption happening when you copy the photos to your PC, rather than there being any problem with the CF card itself. This could be due to a bad card reader, USB cables, or USB port. USB 2 card readers used in conjunction with UDMA7 CF cards are also known to be problematic and can even physically damage your memory cards(!).
Try copying the photos off using a different approach, e.g.via a USB cable plugged directly into the camera rather than using a card reader and see how you get on.