yahoo redirect malware

You have adware/malware installed. Use  Malwarebytes Anti-Malware for Mac. It may be necessary to run more than one scan. After scanning a couple of times, restart the computer and test. If necessary, follow the manual instructions.  Do not download any other programs that are listed in the articles.  

See if the below helps. I would scroll down to the below or you might fall asleep.

Step 1. Eliminate Yahoo Redirect from Windows.    

Step 2. Delete Yahoo Redirect from Mac OS      

Step 3. Uninstall Yahoo Redirect from Internet Explorer      

Step 4. Remove Yahoo Redirect from Microsoft Edge.     

Step 5. Erase Yahoo Redirect from Mozilla Firefox.   

Step 6. Get rid of Yahoo Redirect from Google Chrome.    

Step 7. Eliminate Yahoo Redirect from Safari.   

https://www.2-spyware.com/remove-yahoo-redirect-virus.html.    

Go to Safari Preferences/Extensions, uninstall any you don't recognize, and then turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

 Safari/Preferences/General - see what the Home Page is set to. If something you don't recognize, see if you can replace it with something you want.

 Safari menu/Clear History.

 System Preferences and remove any Profiles you see.

Yeah Bob - That Yahoo is a real pain - I have been fighting with YAHOO for a long time. I'd get rid of it and all of a sudden it would come back. I have Fios and sometimes wonder if Verizon has anything to do with it since they and Yahoo are now playing together. I keep Chrome just like you but decided to try DuckDuclGo -- I couldn't be more satisfied. It is just a wee bit different then Google search, but works the same way. The only time I see Yahoo now is when I click on a new item in the Drudge Report and that particulate news link goes to Yahoo News.