The external monitor gets turned off by default when the Macbook monitor lid is closed. Here is how you can override this behavior. Open terminal & execute the sudo pmset -a disablesleep 1 You can reverse this setting by running the below command in the terminal sudo pmset -a disablesleep 0 The other regular way for the external monitor to remain ON is as below: Connect to power. Connect to external monitor. Close lid.
To set a PDF viewer as the default on Mac OS X: Select any PDF file from Finder. Control-click to open the menu. ... Choose Get Info from the menu that opens. ... From the Open with: section in the new window that opens, select your preferred application, such as Adobe Reader or Preview. ... Click the Change All button.