Yes, usually Photoshop gives me an error, "this file can't be save cause other soft is using it blah blah..." and have to close C2 first, do my stuff, reopen it and images are replaced with new ones
This time I didn't get that info (that's why i remembered that, bit odd) and after that could normally save and close project but C2 stayed open. Only ending process in tasks manager can close it.