safari reopens after force quit

Download this program which was written by Thomas R, a long time poster. The program will search for malware/adware The program will do the work for you which makes it easy. 

Malwarebytes Anti-Malware for Mac      10.10 and later

Malwarebytes uninstall

I ran a malwarebytes free Antivirus scan, I also looked in activity monitor. Activity monitor showed the maftask process... ...a worm that just eats up empty memory and slows system down. Malwarebytes found and removed it free. But it also found remnants of other adware. I removed those as well. Safari still didn't react well.

I cleared the cookies and emptied the cache. All done. No more random opens. No more quit only to have it pop back open. No more force quit only to have it open right back up.

I suggest you run a virus scan, just in case, and even if its clean, clear your cookies, and clear your cache in safari, close it, then reopen while holding down the shift key. This did it for me.

You are welcome. Glad to help.