Help! "Unsupported Image Format" message on random images

Hey guys. I'm new here as I just got my first Canon. As I import my images I've been having issues. Most of them import just fine but a few (maybe one out of every 10-15) will say "unsupported Image Format" Why would only a few of them be unsupported. They are all taken in RAW. I use Apperture 3.3 (recently updated my software to the 3.3 from 3.2)

My troubleshooting is hard to narrow down since I just got a new to me camera (it is a 5d classic), new cf card (I used to use an SD card) (it is not a fast speed one, I wonder if this could be an issue?) I am uploading through the slot in my Canon MP180 Pixma printer.

I have also had issues on import since using the new camera and CF card. It loads very slowly! I had heard updating to 3.3 in aperture should make import faster, so it must either be the card, files (which are smaller than my old raw files actually) or using the printer instead of directly into my iMac. If I don't format my card, I'll have to restart the computer when putting my CF card in or it won't even detect the new photos I've taken with it, only the old ones.

My biggest concern is the "unsupported format" message though. I want my photos back! Thank you for any ideas or advice!

update: if I redo the import selecting only those photos it will not give the error message but imports them just fine. I should not want to be doing this for each import though. Anyone have a thought on what might be causing the error?

I don't think using the printer to Import is the best idea, and it could be part of the problem.

My suggestion would be to buy a card reader and use it, at the minimum a USB2.0 or Firewire 400 card reader. Or, if your Mac supports USB3.0 and/or Firewire 800, I'd go that route if you can find a compatible reader at a decent cost.

Going that route should be a big improvement speed-wise as well as for reliability, since the card reader plugs right into your computer and appears as a "removeable drive" that the computer talks directly to without requiring the added drivers that the printer connection needs. And, as far as speed, just a USB2.0 reader would be a lot faster than plugging your camera directly into the computer, don't try that with the 5D Classic!

Thanks for the suggestion on a card reader. I didn't realize it would slow it down to use the printer as the reader.

Update: the "unsupported format pictures" seem to open up when clicked on an hour after importing.

I started using the CF slot in my Canon MG5150 printer as it was already plugged into a USB slot so I did not have to un plug something else to plug in the card reader. I suppose I should get another hub, after I blew up the last one, but I digress. The slot in the printer seems to run just as fast as if I use my multi slot USB2 card reader.

Al

Sorry should have said this is on Vista

What you can do is plug your camera into your computer to transfer the photos. If you stop seeing error messages, then its probably your printer's card reader. You can also try an external card reader too.

To prevent errors in general, format your card with your camera once your photos are transfered into your computer.

Also what type of cf card are you using and where did you buy it. Theres been counterfeit CF cards being sold on sites such as Amazon.com by third party sellers. Bad cards might cause corrupted files.