yahoo redirect

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

Step 2. Delete Yahoo Redirect from Mac OS      https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-mac-os-x

Step 3. Uninstall Yahoo Redirect from Internet Explorer      https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-internet-explorer

Step 4. Remove Yahoo Redirect from Microsoft Edge.      https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-microsoft-edge

Step 5. Erase Yahoo Redirect from Mozilla Firefox.    https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-mozilla-firefox

Step 6. Get rid of Yahoo Redirect from Google Chrome.    https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-google-chrome

Step 7. Eliminate Yahoo Redirect from Safari.    https://www.2-spyware.com/remove-yahoo-redirect-virus.html#h-safari

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