According to Apple, MacBook Air/Pro/Retina support the closed-clamshell mode, which allows keeping the MacBook ON when the lid is closed. Link from Apple site So I have my MacBook Air AND Pro (both Yosemite) setup like this: 1). Connected to Bluetooth Keyboard (Logitech K810) and Mouse (Anywhere MX2). These 2 peripherals can be used by both MacBook without re-pairing. I.e. Press F1 -> MBA, Press F2 -> MBPR. 2). Connected to an HDMI Hub with switch to allows 3 video source (MBA, PC, Xbox, etc.) to connect to 1 external monitor I keep the MBPR lid open but for the MBA, I keep the lid closed (using Twleve South BookArc). The setup above work, BUT, the MBA keep going to sleep after 1 hour. Is this because: 1). When I switch the peripherals bluetooth connection to the MBPR, the MBA show a message that Keyboard/Mouse connection is lost. OR 2). When I switch the HDMI connection to the MBPR, the MBA revert back to single-display mode. Any ways to keep the MBA awake with the above config?