Stranger's Keychain Info Popped Up
So I was logging into an online account on chrome when a random person's username popped up in my autofill when I typed the first letter of my own username. I looked into my keychains and can't seem to find the file for this stranger's username. Any idea why this occurred? Is it sketchy?
MacBook Pro with Retina display, OS X Yosemite (10.10.4), null