Night Shift Not Working on Mac: How to Fix It

Why is Night Shift not working - what are the most likely causes?

Night Shift stops working for a handful of well-understood reasons. The most common is simply that the schedule has been accidentally set to Off or the colour temperature slider was moved back to the coolest position, making the effect invisible. Beyond user-facing settings, the next most frequent causes are a conflicting ICC colour profile, Location Services being disabled (required for the Sunset to Sunrise schedule), incompatible display hardware, or a software bug introduced in certain macOS point releases.

Apple introduced Night Shift in macOS Sierra 10.12.4, released in March 2017. The feature works by shifting the display's output towards warmer colour temperatures - reducing the proportion of short-wavelength blue light that research has linked to suppressed melatonin production. A 2015 study published in the Proceedings of the National Academy of Sciences found that evening exposure to blue-enriched light delayed the circadian clock by approximately 1.5 hours compared to dim incandescent light. Night Shift was Apple's built-in response to this research.

Because Night Shift operates at the display driver level through the CoreBrightness framework, it can be disrupted by colour management software, custom ICC profiles, display drivers for non-Apple monitors, and bugs in the system daemon that manages its schedule. Understanding which category your problem falls into determines the correct fix.

How do you check if Night Shift is properly enabled?

The first step in any Night Shift fix is confirming the feature is genuinely enabled and configured correctly - not simply set to a schedule that has not yet triggered, or to a warmth level so subtle it appears inactive.

Open System Settings > Displays > Night Shift. You will see three things to check:

1. Schedule: If this reads Off, Night Shift is completely disabled. Change it to Sunset to Sunrise for automatic activation, or select Custom Schedule to set specific From and To times.
2. Colour temperature slider: If the slider is positioned at the far left (Less Warm), the colour shift is so minimal it may be imperceptible on many displays. Drag it towards More Warm to confirm the feature is actually applying a change.
3. Manual override toggle: The Turn On Until Tomorrow checkbox forces Night Shift on immediately regardless of schedule. Toggle this on to test whether Night Shift works at all outside of its schedule.

If Night Shift works when manually forced on but not on its schedule, the issue is almost certainly a Location Services problem (see below) or a schedule configuration error rather than a deeper software fault.

Why does Night Shift need Location Services, and how do you enable them?

Night Shift's Sunset to Sunrise schedule requires your Mac's current location to calculate the precise local sunset and sunrise times. Without location access, macOS cannot determine when those transitions occur, and the schedule will not fire. This is one of the most commonly overlooked causes of Night Shift appearing to do nothing.

macOS calculates solar events using the device's GPS coordinates (on MacBooks with cellular) or network-based location. Location access for Night Shift is controlled separately from app-level permissions and sits under a System Services toggle rather than in the per-app permissions list.

To enable it, go to System Settings > Privacy & Security > Location Services. Scroll to the bottom and click System Services. In the list that appears, find Night Shift and make sure the toggle is on. If it was previously off, open System Settings > Displays > Night Shift and re-select Sunset to Sunrise to force macOS to recalculate the schedule.

According to Apple's own documentation, Night Shift uses your location to determine local sunrise and sunset times and does not store or share this information. The location request is made locally on the device. If you would prefer not to enable location services at all, switching to a Custom Schedule with manually entered times removes the location dependency entirely.

Can a colour profile (ICC profile) stop Night Shift from working?

Yes - custom ICC colour profiles are one of the most persistent and least obvious causes of Night Shift appearing broken. When a third-party colour calibration profile is active, it can override the colour rendering pipeline that Night Shift uses, resulting in either no visible change or erratic colour behaviour when Night Shift is enabled. In some cases, Night Shift will appear greyed out entirely when an incompatible profile is active.

ICC profiles are widely used in colour-critical workflows. Design tools like Adobe Photoshop, Lightroom, and Calibrite's Display CAL software write their own profiles to the display. If you have calibrated your display, switched profiles for a project, or installed third-party display management software, there is a good chance a non-default profile is now active.

To check and fix this, open System Settings > Displays, then click Color Profile. The dropdown shows the currently active profile. Switch it to the default profile for your display - on a MacBook Pro this will be something like Color LCD or Apple Display, on an iMac it will be iMac, and on a Studio Display it will be Apple Studio Display. After switching, re-test Night Shift.

Does Night Shift work on external monitors?

Night Shift does not work on most third-party external monitors. Apple has explicitly documented this limitation: Night Shift applies only to supported Apple hardware displays and a small number of Apple-branded external displays.

As of 2026, Night Shift is confirmed to work on the built-in displays of all supported Mac models, the Apple Pro Display XDR, and the Apple Studio Display. It does not apply to LG UltraFine displays (even those sold by Apple), Dell monitors, BenQ monitors, or virtually any other third-party display connected via Thunderbolt, USB-C, HDMI, or DisplayPort.

Apple maintains a full hardware compatibility list at support.apple.com/en-us/101662. If your external monitor is not on this list, Night Shift will simply not apply to it, and no amount of troubleshooting will change this - it is a hardware-level limitation, not a software bug.

This is one of the most significant practical limitations of Night Shift for users with multi-monitor setups. A developer or designer working on an external 4K monitor for 8 or more hours a day is getting no colour temperature benefit from Night Shift at all. Third-party tools like Solace apply colour temperature changes via a different rendering path that works across both built-in and external displays, making them a more complete solution for multi-monitor workflows. For a detailed comparison, see Solace vs f.lux.

Does enabling True Tone alongside Night Shift cause problems?

True Tone and Night Shift can interact in ways that produce confusing results. Both features adjust the display's colour temperature, but they operate independently: True Tone responds to ambient light measured by the Mac's sensors, while Night Shift applies a fixed scheduled offset. When both are active simultaneously, the combined effect can produce colour temperatures that are unexpectedly warm or shift in ways the user did not intend.

For example, if you are working under warm incandescent lighting in the evening, True Tone will shift the display warm to match. Night Shift then adds its own warm offset on top of that. The result can be an extremely orange-tinted screen that some users find disconcerting, leading them to believe something is broken when in fact both features are working correctly - just additively.

If colours on your Mac look unexpectedly warm or keep shifting unexpectedly, the first diagnostic step is to disable True Tone temporarily at System Settings > Displays (uncheck the True Tone checkbox) and observe whether the Night Shift behaviour becomes predictable. For a thorough explanation of how to use both features together productively, see How to Use True Tone and Night Shift Together on Mac.

Why does Night Shift reset after waking from sleep?

This is a documented bug that has appeared in multiple macOS releases. When a Mac wakes from sleep, the display subsystem reinitialises, and in affected versions, the Night Shift daemon does not correctly reapply the active schedule after that reinitialisation. The result is a display that returns to its uncorrected colour temperature until Night Shift is manually toggled off and on again.

The wake-from-sleep reset bug is most commonly reported on Mac models with discrete graphics, on machines connected to external displays, and following macOS point releases that include display driver updates. It has been observed in macOS Ventura 13.1 through 13.3, Sonoma 14.0, and isolated Sequoia builds.

There are three practical fixes for this bug:

• Update macOS - Apple has patched this in subsequent point releases. Open System Settings > General > Software Update and install any available updates.
• Restart SystemUIServer - open Activity Monitor (Applications > Utilities > Activity Monitor), search for SystemUIServer, select it, and click the Force Quit button (the X icon in the toolbar). macOS restarts it within seconds, and Night Shift typically reactivates correctly.
• Delete the display preferences plist - open Terminal and run: rm ~/Library/Preferences/com.apple.preference.displays.plist, then restart your Mac. This resets display preferences to factory defaults and resolves cases where a corrupted preference file is causing the daemon to fail on wake.

What is the complete troubleshooting checklist for Night Shift not working?

Work through these steps in order. The majority of Night Shift problems are resolved by step 4 or earlier; steps 5 through 10 address less common but more persistent issues.

1. Check the schedule setting - System Settings > Displays > Night Shift > confirm Schedule is not Off, and that the warmth slider is not at the coolest position. Use the Turn On Until Tomorrow toggle to force Night Shift on immediately for testing.
2. Verify Location Services - System Settings > Privacy & Security > Location Services > System Services > confirm Night Shift is toggled on. Required for the Sunset to Sunrise schedule.
3. Check your colour profile - System Settings > Displays > Color Profile > switch to the display's default profile. Custom ICC profiles frequently block Night Shift's colour rendering.
4. Check display compatibility - if you are primarily using an external monitor, confirm it is on Apple's compatibility list. Night Shift does not apply to most third-party displays regardless of settings.
5. Isolate True Tone interaction - temporarily disable True Tone at System Settings > Displays and re-test. If Night Shift becomes predictable, the issue was additive colour temperature shifting from both features.
6. Restart SystemUIServer - Activity Monitor > search SystemUIServer > Force Quit. Resolves the wake-from-sleep reset bug without requiring a full restart.
7. Update macOS - System Settings > General > Software Update. Several Night Shift bugs were fixed in point releases.
8. Delete the displays plist - Terminal: rm ~/Library/Preferences/com.apple.preference.displays.plist, then restart. Resolves corrupted preference files.
9. Test in a new user account - System Settings > Users & Groups > create a new administrator account, log in, and test Night Shift. If it works in the new account, the issue is user-specific (corrupted prefs or a conflicting login item).
10. Switch to Solace - if Night Shift continues to fail after the above steps, Solace applies colour temperature changes via a different rendering path that bypasses all the Night Shift-specific failure modes described above.

When should you use Solace instead of Night Shift?

Solace is worth considering as a permanent replacement for Night Shift in any of three situations: Night Shift keeps breaking despite troubleshooting, your workflow includes external monitors that Night Shift does not support, or you want more precise control over colour temperature scheduling than Night Shift offers.

Solace is a macOS menu bar app ($4.99 one-time purchase, no subscription) that schedules both colour temperature changes and dark mode activation on a daily schedule. It works on macOS Sequoia and later, collects zero data, and processes all scheduling calculations on-device. Because it does not use the same CoreBrightness Night Shift daemon, it is not affected by ICC profile conflicts, wake-from-sleep resets, or Location Services failures. For users who have tried every Night Shift fix and still experience unreliable behaviour, Solace is the most dependable alternative available. For a side-by-side feature comparison, see How to Reduce Blue Light on Mac Beyond Night Shift.

Night Shift's colour temperature shift tops out at approximately 3000–3500K at its warmest setting, according to measurements taken with a spectrophotometer by several independent Mac hardware reviewers. Solace allows you to specify a target warmth value and apply it on a precise timed schedule - including starting the warm shift earlier in the afternoon rather than only after sunset, which research suggests produces greater circadian benefit for people who work past 9 PM.

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