I think this is a bug in the editor. I fixed it by right clicking the 'Scene' tab and clicking 'Close tab'. Then went to Window->Scene and the new scene view worked fine and it stopped outputting any errors.
I met it also. but the error pops up only when I run the game in editor. I solve it by check on the button "Maximize on play" in the Game Tab to make the game run in a single window. It will pop up again when I check off the button. So from now no, I need run my game with the button check on. Aha! God bless you, may it works for you!!!