I recently returned a battery to TT Support as it was constantly giving me problems with the SD card and the Can't Write To SD Card screen. Now my second battery is showing exactly the same problem. BUT it only happens if I remove the battery from the camera. If I leave the battery in and and turn it off and on, even allowing hours I don't get the issue. I only use cards that TT say are ok.
I am thinking at this stage it is not the battery but the camera. Anyone else suffered this. I am now going to report the issue to CS