K20D Continous shooting and surprise...

I'm not a fan of taking tens of pictures by one finger press on shutter and never really used it (apart of some testing), but today I had a perfect subject to actually let camera shoot at max.
So, I got my subject in place, shutter pressed, got to the point where buffer has got full and camera slows down a bit, took few more pictures depressed shutter and pressed it again to take few more pictures after some 2 seconds (camera was still saving previous ones, and was taking pics on a slower speed (buffer full like).
Not suspecting problems, have moved pics on the PC and... Camera saved 18 PEFs (PEF was is use) all having sizes between 15.9MB to 16.5MB (so pretty good).
Tried to open them in Irfan and: 7 of them display only embedded thumbnail, tried to open them in pentax photo browser and ufraw, but only got message saying that file is corrupted or software was crashing. Another 3 pictures were showing only part of frame from 15% to 40% (ish) lines (from top to bottom). Remaining 8 seems to be ok.
Memory card was Extreme III SDHC, 1/400sec, 800ISO. I did one more test later one, but it was darker and shutter speed was slower and all pics were saved correctly.

Sorry to hear that, it can be so many things that's it is hard to tell.

Glad it isn't a re-returning problem.

the first thing I would do is try to re-create the problem.

same card, fast shutter speed (point it at a light source if necessary so you can see if the shots are recording correctly).

If you can re-create it this way the first thing I would try is a different memory card, then a fully charged battery.

If neither of these eliminates the fault then you have a possible camera fault.

good luck, I hope it's the card since those are fairly cheap and I believe Sandisk have a lifetime warrenty.

I will try it as well with my K20D and a Extreme III sdhc card.