The MacBook will go into sleep mode when the screen is closed. In order for the MacBook to wake up after being put into the Henge Dock there must be a solid power connection established, must be connected to an external display and the MacBook must be connected to its peripherals (keyboard, mouse...) prior to docking. To wake it up once docked, just hit a few keys on your keyboard or mouse and wait. It can take as long as a minute for the computer to wake back up in the closed position, especially when using a wireless keyboard or trackpad. If that doesn't work, double-check that the MagSafe power supply is securely connected because the computer must be receiving power in order to operate in the closed position.
The most common reason users experience difficulty waking up their device while using the Henge Dock is because a solid connection is not being made between the MagSafe Power Adapter and the MacBook. Below are some troubleshooting tips if there is difficulty waking up the device.
If you have a dual graphics card it can occasionally cause the MacBook to hang when coming out of sleep mode. In System Preferences >> Energy Savings disable Automatic Graphics Switching to see if that will resolve the issue.
Try uninstalling and reinstalling the MagSafe Power Adapter. Loosen the set screw and remove the power adapter from the docking station. Ensure that you have properly chosen and installed the correct MagSafe Adapter Tool (chicklet A, B, C, D, or E, depending on the model). While sitting in a chair, place your MacBook into the docking station, flip the MacBook and dock over as one unit, and hold them in your lap so that the MacBook is between your legs and the bottom of the dock is facing up at you. Insert the MagSafe Power Adapter with the tool attached through the corresponding port void inside the docking station. You will usually be able to feel the magnetic "tug" when you have made a solid connection with the power adapter, and in some models you will be able to see the LED light up. Tighten the set screw to secure the MagSafe Power Adapter in place, pull the cable(s) through the cable organizer, and carefully flip the MacBook and dock back over and place them on a flat surface.
If the MacBook still will not wake, troubleshooting continues by isolating the computer and peripherals from the docking station. Remove the MagSafe Power Adapter from the dock (and Thunderbolt cables) and unplug all connections from the preinstalled cables. Setting aside the dock and all included Henge Docks cables, connect the peripherals (keyboard, mouse, display, etc) to the MacBook. With the MacBook still closed, attempt to wake the computer again. If the computer wakes, one or more of the connections was not seated properly in the dock. Perform the same port reinstall as listed above, disconnecting and reconnecting ALL of the included Henge Docks cables (USB, Audio, Mini DisplayPort, etc).
Lastly, you can try downloading an app to turn off the automatic sleep cycle that occurs when you close the lid of your MacBook. (You can still manually set your MacBook to sleep.) Caffeine and InsomniaX are both great options. It may seem obvious, but be sure the outlet is not hooked up to a light switch that is turned off.
If none of these solutions work, the issue is independent of the docking station and we suggest that you seek service help for your computer.