Lightroom :: Images Imported 0 Some Ruined With Blank White And Color Banding

I'm using Lightroom 4..i've been importing my RAW images from my external harddrive. Some show up in the catalog as ruined with a blank white section and color bands.  I've checked the actual image on the external hard drive and it is fine. I've deleted the ruined files from the LR catalog, then re-imported those problem ones... still come in as white with banding.  I've even tried deleting them from the catalog, then from the hard drive... then back onto the HD from the camera, then back into lightroom. Some look ok until I look at then in loupe view and the same problem happens.  Mean while the images on the HD and on the camera's CF card are fine.