Thanks again for that info. My goal was to have two exact libraries on my desktop and notebook. I had some new books on the notebook that needed to go onto the desktop.
I may have had the Calibre interface open on the desktop computer I was copying into from the USB drive which held the new files from the notebook. I did have the new metadata file on the USB but will the metadata file replicate anew since it has the same name in both sources but different mbs?