5D II corrupted files
I just had similar problems with 1dmk2n,using sandisk extreme cards
The brief view is either the card is defective or
there is a problem importing the images into Bridge .
I tried accessing the images on the card using DPP generally (50% of images) were accessible and OK and can be processed with Canons software but not Bridge.
Sandisk blame Adobe,Adobe blame Sandisk.
This appears to be a fault within the card ,best replace it and see if Sandisk will replace.
But try the option of using DPP to access the image(s) rather than importing to a folder first,just in case you can salvage some.