Yes, the root cause was a worn out micro SD Card that could not fully copy from an SD card reader plugged into a USB port. This micro SD memory card is no longer mountable so no further testing with File Explorer is possible.
The purpose of this post was only to alert you about how Dopus handles this particular circumstance (which may or not be the same as File Explorer would respond). My thinking was that Dopus would handle the recurring error by timing out and allowing the copy to abort when the "Abort" button is clicked.
Thanks for your response.