Where does Fritzing store known parts

Where does Fritzing store it’s list of “known” parts, i.e. which file?

The reason I ask is because Fritzing has lost my part I have been creating but when I attempt to load the .fzpz file back into Fritzing it displays a message saying “There is already a part with id … loaded into Fritzing”.

I would like to get rid of that part that Fritzing “thinks” is loaded and re-load my part.

I only know Win7

Each part has an ID#, and reloading that ID# again and you get that message. I remove it from here. - C:\User\X\Documents\Fritzing\parts\user

If you remove a part in a FZ bin you have to close FZ and restart FZ again, or you get that,