Safari will not close on my desktop

 1. Remove Adware

     Run  the latest release of Malwarebytes for Mac to remove malware/adware, if installed on your Mac.

     For instructions:  Install Malwarebytes for Mac          Uninstall Malwarebytes for Mac

     Click the “Scan Now” button. Once done, quit Malwarebytes for Mac.

     Restart the computer and relaunch Safari holding the shift key down.

     Repeat the scan couple of times.

 2. Additional steps to take if necessary.

  1. Remove unknown extensions:  Safari > Preferences > Extensions

      https://support.apple.com/guide/safari/use-safari-extensions-sfri32508/mac

  2. Reset search engine:    https://support.apple.com/guide/safari/customize-your-search-ibrwe75c2a3c/mac

  3. Reset  Homepage.   https://support.apple.com/guide/safari/set-your-homepage-ibrw1020/mac 

  4. Restart your Mac. Relaunch Safari holding the Shift key down.      

You may  have adware/malware installed. Try downloading 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. It may be necessary to run more than one scan. After running the scans, restart the computer.

Malwarebytes Anti-Malware for Mac      10.10 and later

Malwarebytes uninstall

Reboot the computer.

You are welcome.