about:blank MacBook Pro can't remove (menu appear twice)

Hi, I am a MacBook user for 10 y. This is new to me. When I open Safari 11 in High Sera, my Top Sites page does not appear and its stays on the desktop page. When I click and hold the Safari icon, I see 2 about:blank pages open. I can use New Window and then I get my Top Sites. I used Malware Bytes FREE version, but it does not do anything. I went into the Safari preferences and unblock the only extension there is and quit using the force quit and restarted Safari. No luck. I also deleted all caches from the computer manually. Can anybody help to remove. I find buying Malware Bytes very expensive at 50 $ Canadian. Thanks.