I cannot update to Safari 12
I've been trying to update to Safari 12 but the app store won't let me. It says. “Safari” cannot be updated because its extensions are in use by “Spotlight”. Click OK and quit the application". Safari wasn't open and I don't know how to shut down spotlight or shut off extensions. Please Help. Ron
iMac (Retina 5K, 27-inch, Late 2015), OS X El Capitan (10.11.6)