Windows 10's useful error message

Microsoft started rolling out Windows 10, its shiny new operating system from 29th of July and there have been reports of bugs and issues with installing the Windows 10 operating system on PC/Laptops. Of course, with new OS come new error messages but this one takes the cake.Question time: which mail application of which operating system has a dialog that reads "bummer"? Your prize will be a firm handshake, to be administered by yourself or by whoever is standing closest to you.