partial downloads starting over after closing opening nb

It used to be that partially completed downloads would continue after closing and re-opening NB (6.50: 00 36 7B 6F FA 6D).
Now the files dissappear from my TEMP (different than ultimate destination) file and the whole d/l starts over.
Now the files dissappear from my TEMP (different than ultimate destination) file and the whole d/l starts over.