If you are experiencing issues related to the following functions on your MacBook, you may need to reset the NVRAM (NonVolatile random-access memory) or PRAM (Parameter Ram). Both of these parts of your Mac store similar information and the steps for resetting them are the same:

• Sound Volume
• Display Resolution
• Startup-Disk Selection
• Time Zone

Some examples of issues that are related to the settings above can include when your Mac starts up and displays a question mark before booting. Constantly having to change your time zone even when you haven't changed where you are. Your volume controls not saving their settings is another common issue fixed by following the steps below.

1. Shut down your Mac, then turn it on and immediately press and hold these four keys together: Option, Command, P and R. You can release these keys after counting to 20 (One one thousand, two one thousand...)

You can release the keys once you either hear a startup sound or after the Apple Logo appears and then disappears a second time.

2. When your Mac finishes starting up, you might want to open System Preferences (Click the Apple in the top left and then System Preferences) and adjust any settings that were reset, such as sound volume, display resolution, startup disk selection, or time zone as all will be reset to factory defaults.

NOTE:  If your iMac is experiencing similar issues - it's important to know that iMacs have a small battery that helps the NVRAM retain settings when the Mac is unplugged. If the issues above are ocurring on an iMac , its best to reach out to IT for support.