How to Turn off "Product Shipped" email for digital products?

I am selling digital products only. I have selected the "no shipping" from the shipping tab settings in Marketpress.
The problem is the customer is getting 2 emails immediately at order confirmation. One is the product receipt and download which is perfect. Unfortunately they are also getting a second email that initially said "your product has shipped". How do I turn off the 2nd email triggered at shipped status which happens instantly at purchase for downloadable products?