After coming back from Muir woods with a CF card full of photos, I tried to dump them on to my mac. I’ve done this many times before without problems, but not this time. I should have suspected something funny when Aperture didn’t pop up automatically.
I manually started Aperture, then when to the import screen and looked at my CF card.. and the list of images I got looked like what was on the card before I took it out, reformatted it, and then shot a set of new pictures. Crap.
I thought there might just be some weird in-memory state or something, so I took the card out and rebooted the machine, and reloaded the card. Now I get a bunch of blank images.
Oddly, the last few images on the card are full versions of what was on the card before I formatted.
Either my camera failed to format the card properly (which is hard to believe, because I could preview the shots on the camera), or my Mac did something funny.
It probably didn’t realize the CF card had been ejected, and left some file system state cached in memory, then tried to the write that back out when the media appeared again? I don’t know how else you can explain old state that should have been destroyed with a format suddenly returning.
Isn’t this why you’re supposed to be really conservative about write caching on removable flash media? I know this makes performance crappy, but that’s a lot better than losing all your images.
Two hours of photo-taking, down the drain.
Lesson Learned: Make sure your mac knows your card reader is empty before inserting a new card.