|Did you follow the procedure to 'safely remove' the camera before disconnecting it from the computer?|
For what's it's worth I rarely connect and disconnect USB devices unless the computer is off. I don't trust the 'hot plug' technology.
I came across this not too long ago:
but haven't tried it. You might check into it if you're forgetful or need additional protection. It looks like it's got a 30 day free trial and then costs $19 for a lifetime license.