2015D was an ABC timeline and a year in the 21st century. It was created when Microsoft's failed visions of the future were actually a success.
On July 15, 2015, Doc Brown and the senior vice president of Microsoft's Server and Tools business, Bob Muglia, arrived in the DeLorean time machine. To their horror, they saw that Microsoft's failed digital assistants, Clippy and Microsoft Bob, were now holograms that controlled everything.
This timeline was overwritten with 2015E once Doc took Bob Muglia back to April 4, 2007 and Bob gave a revised version of his "Visions of the Future" speech.