First it was exif, now it is entire images. This is from Canon Officially:
"...We have discovered that the original image data of TIFF (RAW) images shot with an EOS-1D or EOS-1Ds Digital SLR Camera, and rotated or edited using Windows Explorer or Windows Gallery on a computer running Windows Vista, will disappear from the computer's memory...".
See also a warning on the same subject (image data loss in Vista) from Microsoft
"...We have discovered that the original image data of TIFF (RAW) images shot with an EOS-1D or EOS-1Ds Digital SLR Camera, and rotated or edited using Windows Explorer or Windows Gallery on a computer running Windows Vista, will disappear from the computer's memory...".
See also a warning on the same subject (image data loss in Vista) from Microsoft