Have warning sign after security update. Computer frozen
Frozen screen with warning sign after security update
menu/Restart computer. Try restarting Safari with the shift key held down. 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.
