Weird black circle symbol asking for my password at b
Mac Pro 5,1 High Sierra. I just started getting a weird symbol at boot, and asking for my password. It looks like a black record album with red near the center that looks like a record label, and small hole in the center, and a silver outside rim (looks like an album on a turntable). I'm also getting asked for my password each time I boot up. What is it,have I been hacked?