Apple explains that reducing the blue light and shifting the color balance toward the warm end of the color spectrums produces an image that’s easier on the eyes. Apple also says that less eyestrain in the evening hours promotes better sleep patterns. Finding the controls for Night Shift and setting up the service can be a bit of a chore, but it doesn’t take long to get Night Shift working on your machine.

Night Shift Minimum Requirements

Night Shift has fairly stringent minimum requirements, and these requirements often trip up users. You may think that your Mac is ready for Night Shift when, according to Apple, your Mac or displays aren’t supported. To use Night Shift, your Mac must be included in the following list and run macOS Sierra (10.12.4) or later:

Mac mini: late 2012 or newer iMac: late 2012 or newer Mac Pro: late 2013 or newer MacBook 12-inch: early 2015 or newer MacBook Air: mid-2012 or newer MacBook Pro: mid-2012 or newer

Night Shift also supports the following external displays:

Apple LED Cinema DisplayApple Thunderbolt DisplayLG UltraFine 5K DisplayLG UltraFine 4K Display

If your Mac meets these requirements, you should be able to enable Night Shift and use its features.

How to Enable and Manage Night Shift on Your Mac

Night Shift’s primary interface has been added to the macOS Display System Preferences. You can use the Display preferences to enable Night Shift, set a schedule, and adjust the color temperature of the display when Night Shift is enabled. To do so, complete the following steps:

Use Notification Center to Control Night Shift

The Display window in System Preferences is the primary interface for Night Shift, but you can also use Notification Center to turn Night Shift on or off manually. To do so, complete the following steps:

Off disables Night Shift.Sunset to Sunrise turns Night Shift on at sunset local time and off at sunrise local time.Custom enables you to select the time Night Shift turns on and off.

To turn Night Shift on regardless of the current time, select the Manual check box. Night Shift remains enabled until sunrise the following day or you turn it off. Adjust the Color Temperature slider. Using this slider, you can set how warm or cool the display appear when Night Shift is turned on. Select and hold the slider to see a preview of how your display will look with Night Shift turned on.

Troubleshooting Issues With Night Shift

Mac users have run across two issues with Night Shift. Here’s how to troubleshoot them.

Can’t See the Night Shift Controls

If you don’t see the Night Shift controls, the most likely cause is that your Mac doesn’t meet the minimum requirements. It can also be an issue if you’re using an external display in conjunction with your Mac’s built-in display. If this is the first time you’ve tried to access Night Shift after upgrading to a Night Shift–compatible version of macOS, you may need to perform a nonvolatile RAM (NVRAM) reset for Night Shift to appear.

Night Shift Color Changes Don’t Appear on the External Display

What if the external display doesn’t show any Night Shift color changes, but the main or built-in display does? Apple says that Night Shift works with external displays but not with projectors or televisions. Both types of external display typically connect through an HDMI port, and that may be the actual issue: Many of the people reporting external display problems are using an HDMI connection. Instead, use a Thunderbolt or Display Port connection.

Alternatives to Night Shift

Night Shift on the Mac works best with newer Mac models. Night Shift uses something called the CoreBrightness framework, and when macOS doesn’t detect a recent version of that framework, it disables Night Shift. If you absolutely must have Night Shift and are willing to hack your Mac, you can replace the CoreBrightness framework with a patched version that allows Night Shift to run. A better solution is to install a blue light filtering application such as F.lux, an application that performs the same function as Night Shift but runs on both current and older Mac models. It also has additional features, including better support for external displays, the ability to specify apps that disable F.lux (an important consideration when working with apps that require color fidelity), and better scheduling and color temperature control.