Here’s what you need to do if you want to stop your MacBook from sleeping when the lid is closed and even turn on your Mac without opening the lid.
There are a lot of different reasons why you might want to use your MacBook with the lid closed. You might want to plug into an external display and move your MacBook out of the way to free up space on your desk (although you could always use both screens). Alternatively, you might want to download a software update or play music from your Mac and have found that as soon as you close the lid the download or music will stop.
If you want to stop your Mac from sleeping when you close the lid then you’ll find out how to do that below.
One related problem you might come across if you are using your Mac with the lid closed is that when it comes to turning your Mac on it would seem that you have to open the lid to press the power switch… Luckily there is a workaround for that scenario that you might find useful. So we have also included advice about how to turn on your Mac without opening the lid below.
Read more at MacWorld.com