Won't recognize my password

[mlynntn]

I've changed my password three times thinking perhaps I keep forgetting it, even though it's only been a minute since I created it. I've given up on that idea. But every time I enter it, the dialog box pauses, shakes, and then still asks me for username and password. Any ideas why this is happening?

[John Waller]

If you're on a Mac, it's your operating system asking for your local administrator username and password. Essentially, it's requesting permission to install software on your hard drive,