I have two hard drives, the first drive is a ssd which I have installed my OS (windows 10) on. The second is a normal HDD which I use for storage and booting up ubuntu. When I had windows 8.1 I could access it just fine, but when I upgraded to windows 10 it just "disappeared" and I could no longer find it/access it. However, when I boot up ubuntu I can access it again.
Here is the picture of my disk management setup.