I am mystified: first, I have an iMac and a mbp, both running mountain lion. In System Preferences > Security > General > Require Password after sleep or screensaver, I can adjust the time to 4 hours on the iMac, but it goes only as far as one hour on the mpb. To further complicate the matter, when I turn on Filevault, the checkbox for this option disappears on the mpb, so I can't totally disable it, but everything remains the same on the iMac. What exactly is going on here? I really want to disable this feature on the mpb, and I'd really appreciate if someone in the know can show me how to achieve that.