Any one come across this before: I was filming a wedding yesterday, and this error came up on my screen: file name error. The card would no longer let me record anymore footage to it! So I thought, that's ok, I still have the other card in slot B to fall back on. Then later that day, that card did the same thing! I was screwed, had a camera that would no longer record. Luckily I had a 70d to fall back on. I've been using this camera for 7+ months and haven't seen it before. I'm using the latest firmware, any ideas?