How to Keep Your Mac From Going to Sleep
Macbooks and other Apple computer models have a sleep setting that shuts the computer down after a certain period of time. This saves power, and prevents image burning on the computer's display. To prevent the Mac from going to sleep, you must adjust the Energy Saver settings in the computer's preferences menu. This is a simple process, and you can easily access the menu from the computer's desktop.
Click the Apple icon in the top-left corner of the desktop of the Mac computer. Select "System Preferences."
Click "Energy Saver" under the "Hardware" section of the System Preferences menu. There is a light bulb icon above the option.
Click the drop-down box next to "Optimization." Select "Custom." Click the "Sleep" tab. This will open your sleep menu. The menu has two slider bars: one controls when the computer goes to sleep; the other controls when the display goes to sleep. Slide both over to "Never."
Uncheck the box next to "Put the hard disk(s) to sleep when possible." Click the red circle in the upper-left corner of the menu to close it.