Exporting Entities Fail Error


I am uploading some items to the marketplace, and when i get to the stage to export entities I get a pop up message saying export failed, but the json file still saves to my computer with an added file extension to it.

Something like this beertap.json.HjZccp but if I then delete the the letters after the .json and use that It all seems to work fine and my items get accepted onto the marketplace.
I just thought id mention it.