If you are receiving the error Cannot copy file (2): The system cannot find the file specified. when copying files that start with a period / full-stop - for example:
check to make sure your destination device is able to store folders or files that start with a period / full-stop. For example, it is known some NAS devices from QNAP are unable to.
It is also recommended that you check to see if a newer version of the firmware is available for the NAS device.