I had same problem with Sony HDR-PJ240, 64 & 32 Gb cards not readable by camera, but by pc, formatted by PC still would not work or even be recognised in camera. But did the following:
Recovering SD card on Sony camera when No picture on screen (lens cover open),
And memory card symbol flashing.
- Remove memory card
- Go to Settings- Initialize Press upper screen button- “Reset to default settings” click “OK”
- Screen will go blank and reboot.
- If It does not reboot, remove all mains power & battery, wait 15seconds for chipset to reset, install battery & mains power (but Works on a full battery)
- Now put memory card in and reformat or recover, repair using device to format not on PC.
Worked on both my cards 64 & 32 gb Sandisk cards
It seems the device needs to format cards itself. It will be interesting to see if the same reboot / recovery method works on other devices that use sandisk cards!
I hope this helps, I wasted 4 hours trying to resolve this with recovery software and almost went out and bought another card.
