Of course, this would happen. I get all happy about receiving my Canon 5D Mark II today, I take some test shots, and they look sweet after playing around with the new settings for the 5D MII. After importing them into Aperture, you are “happy” to learn that Aperture does not recognize the format 😦 Crap!
Oh well, don’t give up. There is a work around. When Apple lets you down, go to Adobe. And I don’t mean go out and get Adobe’s Lightroom, its version of Aperture. Adobe has an application called Digital Negative (DNG) Converter. This allows you to convert unrecognized raw formats to a workable format in Aperture. This has worked for me before.
The speed of the process will depend on how fast your computer is. These are 21MB raw files you are now dealing with. Download the latest version and copy all of your .CR2 files you shot with the 5D MII into a separate folder.
After you open the DNG Converter application, in section 1, select the folder your .CR2 files are in. For section 2, you can either leave them in the same folder or have the coverted files moved to a new folder. Moving them to a new folder will make it easier for you to import the DNG files. Leave section 3 alone.
For section 4, I would recommend the following options you see on the graphic provided below.