I have a Sony Class 4 SDHC Card SF-16C4 that I had been using in a Raspberry Pi and re-formatted as MS-DOS (FAT) and exFAT with disk utility on my Mac and tried it with a Cannon Powershot A560 and a Cannon EOS Rebel T3i - both reported "No Memory Card" with either format. I then tried using SDformatter on my Mac and still am getting the same error.
BTW, the card is marked as SDHC but my Mac seems to be reading it as SDXC.
Anyone have any clue why the cameras won't recognise the card?
Edit: also borrowed and tried in a Windows XP machine and an older Mac (without a dedicated card slot) and neither of them read it.