I had something similar happen and when I did an internet search, the way to fix it was to clear the internet history, then shut down and restart the computer. I have a MacBook Pro, the mini iPad and the iPhone6 - all of which have Safari.
Even though my daughters told me it was not necessary I have Norton 360 and when it was first put on it found some viruses that my daughters said wouldn't be there. (We also have a full size computer and an HP Laptop.)
Hope you can get this cleared up - it is a royal pain.