[Henry Jackson]

Had precisely the same issue on a 7D with 2 different Kingston 16GB ‘Ultimate’ 266X. I bought the cards at the same time and they both simultaneously started giving me the ‘read error’ messages. A strange coincidence that they both started to go at the same time (roughly 3 months after purchase).

I went out and bought a Sandisk 16GB Ultra (technically slower) and it has worked without a problem thus far. So i personally can’t see it being a speed issue, more a card reliability issue.
Extremely irritating as i was mid documentary and lost a few key shots, you live and you learn, and you definitely get what you pay for…