Safari - pop up issue.

Close pop-up ads

Start by closing any pop-ups that are open.

• If a pop-up on your Mac includes a "Don't show more alerts from this webpage" checkbox, 

       select the checkbox before closing the pop-up.

• If a pop-up won't close:

       On your Mac, force Safari to close. The next time you open Safari, hold down the Shift key while Safari opens.

       This prevents Safari from automatically reopening any windows.

       https://support.apple.com/en-us/HT203987

Safari – Popup takes over

Safari – Popup takes over (2)

Popup remover – Scam Zapper

If the pop-up reloads, force quit Safari (command - option/alt - esc) and reopen with the shift key held down. If that doesn't work, disconnect from the Internet, go to Safari/History and delete the website. Quit and reopen with the shift key held down. Then reconnect to the Internet.

Safari -Tech support scam pop-ups

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