why does my monitor go dark when i close my macbook
why does my monitor go dark when i close my mac book
MacBook Pro (Retina, 13-inch, Mid 2014), OS X El Capitan (10.11.1)
Because Macs are configured to sleep when you close the lid.
What do you want to accomplish with the lid closed?
This is the Mac Pro desktop forum. I requested your post be moved to the MacBook Pro laptop forum.