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During the last session with my Canon 50D, 4 or 5 photos from 180 appeared to be with artifacts: 1 Fullsize 15Mb 3 Fullsize 7Mb

These photos were already broken in preview on camera display, so it can't be usb cord issue. Each jpg is broken the same way as corresponding raw.

How can I troubleshoot the reason?

marked as duplicate by mattdm, Philip Kendall, inkista, Community May 21 '16 at 16:41

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  • Are the *full *RAW files damaged in the exact same way, or just their JPEG previews? – mattdm May 21 '16 at 15:31
  • @mattdm, yes, seems like duplicate, thank you. And yes, full raws are damaged the same way, doublechecked. – moropus May 21 '16 at 16:40

I would start by using a different memory card.

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