"Memory card error" - that was the message on my camera screen after I'd taken a number of photos during the day. It just happened: I hadn't dropped the camera or done anything out of the ordinary.
When I got home, I found my computer couldn't access the photos I'd taken. A quick Google search, and the solution seemed to be easy: just download Recova or Zero Assumption Recovery, and all will be right, won't it?
No, it's not as easy as that! True, these programs get glowing reports in the forums, and I had no problems running them both, but they didn't find the photos. Back to the forum, and lurking there was the comment: often the problem is that the controller on the card is damaged. In this case, there is only one way to get the data back, unsolder the memory chip and directly access the raw data with a programmable chip reader. Software won't help, this is physical damage!
This is w-a-y beyond me, and another browse on the internet suggests that commercial data recovery services don't come cheaply! (I saw one quote for $150).
Morals from the story? Yes, a few. Don't ignore warning signs. I've been told that you usually have warnings that a drive is on the way to failing, and I had been having minor glitches downloading from the camera. Now I think I know why.
And, of course, back-up regularly, which in the context of cameras, means download the images regularly to the computer. I admit that I'm not perfect in this regard, but fortunately in this instance I was up-to-date, so I only lost photos from one day. This was troubling, but it could have been worse.