Hello, Problem: I also got the C:13:01 error after inserting newly bought SONY Memory Stick Pro Duo into my sony V-1 camera. Cause: But in my case the problem was caused by the adaptor from MS Duo to MS (from this small cards to a bit larger ones). The inner connectors simply didnt connect properly, or not all of them. Solution: The solution was to open the adaptor (quite easy - it's all plastic case) and bend the connectors a bit so after inserting the smaller MS Duo they will stick more firmly. Now it works perfectly with both camera and PC. (btw. dont drop or hit or be cruel in other ways to your camera. It was made in Japan, not Russia, and sooner or later this will harm it) Hope this helps those of you who use MS Duo through an adaptor. Final conclusion: very sad, that original SONY Memory Stick with original SONY adaptor (in my case MSAC-M2) does not work with original SONY camera.