Switch Users Option on Lock Screen
I am at a community college setting up new macs for a lab. When someone doesn't log out and let the computer lock up, there is no option to switch users. The computer has to be turned off for someone else to log in. The older macs we replaced showed this option. I just want to know how to get it on the lock screen.
iMac, OS X Yosemite (10.10.3)