I have a strange problem with one of my OMD-EM5 bodies: over a period of several days or weeks, it appears to corrupt its memory card. When this happens, the camera locks up. I can usually look through the EVF, but the camera will not focus and the shutter will not work. When the card is placed in my other OMD body, it locks up and will not work at all. Any images on the card can be downloaded to my computer with no apparent ill effects. No virus shows up when scanning the card with my anti-virus program. I can format the card in my Canon 6D and it will be usable again in the OMD until it again becomes corrupted. This has happened with two different cards, a Transcend and a Sandisk. Any ideas, other than sending it to Olympus repair?