Reading about these strange behaviors that you have with your camera I would also recommend you to try another USB cable.
See a topic that I opened after struggling with strange and not reproducible problems with my camera ( Thread ).
I could get rid of the problem with a new USB cable. I don't want to do marketing for the brand of this USB cables but they are outstanding, already when you plug the cable you can feel that they are much more solid and my camera now works reliable and without problems.

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