True Tone Not Available on External Monitor: What to Do

Why is True Tone greyed out or missing for my external monitor?

When you connect a third-party external monitor to your Mac and open System Settings > Displays, the True Tone checkbox simply does not appear. This is not a bug, a missing driver, or a macOS configuration issue. It is a hardware limitation - and no software update or settings change will add True Tone to an unsupported display.

True Tone works by using ambient light sensors built directly into the display to sample the colour temperature and brightness of the light in your environment. The Mac then adjusts the display's white point in real time to match that ambient light. If the display does not contain those sensors, there is nothing for macOS to read, and the feature cannot function.

Beyond the sensors, True Tone also relies on Apple's proprietary display communication protocol, which is only fully implemented in:

• Built-in displays on MacBook Pro, MacBook Air, iMac, and iPad (2018 onwards)
• Apple Studio Display (27-inch, released 2022)
• Apple Pro Display XDR (32-inch, released 2019)

Third-party monitors - including Dell, LG, Samsung, BenQ, ASUS, and every other non-Apple brand - lack the sensor integration. This is not something that can be added retroactively. Even if a firmware update gave the monitor an ambient light sensor, the macOS True Tone pipeline is designed specifically for Apple display hardware and does not expose a public API for third-party displays to tap into.

Which external monitors support True Tone?

The list of external monitors with full or partial True Tone support is short. Here is the complete picture:

If True Tone is a hard requirement for your workflow, the Apple Studio Display is the only practical external monitor option. At $1,599, it is a significant investment, but it is the only third-party-sized display that supports the full True Tone feature set reliably.

What are the best alternatives to True Tone on unsupported monitors?

The goal True Tone achieves - matching your display's colour temperature to your ambient lighting - can be approximated through a combination of software and hardware controls. The main options are below.

Night Shift

Night Shift is Apple's built-in colour temperature tool, available in System Settings > Displays > Night Shift. It warms the display's colour temperature on a schedule - either a custom time window you define or automatically from sunset to sunrise using your location.

The key difference from True Tone is that Night Shift applies a fixed, scheduled shift rather than a real-time sensor-driven adjustment. You choose when it activates and how warm it goes; it does not respond to changes in your ambient light during that window. For most use cases this is a practical trade-off - if you set it to come on at a sensible time and dial in your preferred warmth, it reduces the blue-heavy light that causes eye strain in the same way True Tone does.

Critically, Night Shift applies to all connected displays simultaneously, including external monitors that do not support True Tone. This makes it a universal solution for multi-monitor setups.

Solace

Solace is a macOS menu bar app that provides more granular colour temperature control than Night Shift, working across all connected displays including external monitors.

Where Night Shift offers a single slider between Cool and More Warm, Solace lets you set precise warmth levels and multiple schedules - for example, a light warming at 2 PM as afternoon fatigue sets in, and a stronger warming from 7 PM onwards for evening work. It runs on a daily schedule with no manual intervention required.

Solace also handles dark mode scheduling, wallpaper switching, and weather-aware changes in a single app - so it becomes a complete display environment manager rather than just a colour temperature tool. All of this applies across all connected monitors simultaneously.

It costs $4.99 as a one-time purchase, requires no subscription, collects zero data, and runs on macOS Sequoia and later.

f.lux

f.lux is a long-established colour temperature tool that also works on all connected displays. It uses a location-based model to gradually warm the display as the day progresses, mimicking the natural shift in ambient light from noon to evening. f.lux uses a subscription model and has been available for Mac since before Night Shift existed.

Your monitor's OSD hardware controls

Most monitors include an on-screen display (OSD) menu accessible via the physical buttons on the monitor itself. Within the OSD, look for a Colour Temperature or Colour Mode setting. Common presets include:

• 6500K (D65) - neutral daylight, the default for most monitors
• 5000K (D50) - slightly warm, good for reading
• 3200K (Warm) - noticeably warm, equivalent to a strong Night Shift setting
• sRGB / Paper - typically 5000K or warmer, intended for extended reading

Hardware colour temperature changes are independent of macOS and apply at the display level. The trade-off is that they are static - you would need to manually adjust the OSD when switching between day and evening use. Software tools like Night Shift or Solace automate this transition for you.

How do you set up Night Shift for an external monitor?

Night Shift works on all connected displays from a single system-level setting. You do not need to configure it separately for each monitor. Here is how to set it up:

1. Open System Settings - click the Apple menu in the top-left corner of your screen and select System Settings.
2. Go to Displays - click Displays in the sidebar. Night Shift applies globally to all connected screens, so it does not matter which display is currently selected.
3. Open Night Shift - click the Night Shift tab or button within the Displays section.
4. Set your schedule - choose Sunset to Sunrise for automatic activation based on your local sunset time, or choose Custom to set a specific start and end time. For external monitor use where True Tone is absent all day, a custom schedule starting earlier (e.g., 3 PM) helps compensate.
5. Set colour temperature to maximum warmth - drag the slider all the way right to More Warm. This gives you the greatest reduction in blue-heavy light that Night Shift can deliver.

Once configured, Night Shift activates and deactivates automatically every day without any manual intervention. Your external monitor receives the same colour shift as your built-in display.

How does Solace handle multiple displays?

Solace applies colour temperature changes at the system level, which means all connected displays - including external monitors - shift together when a scheduled warmth change fires. There is no per-monitor configuration required and no additional setup needed for external displays.

This system-wide approach makes Solace particularly useful for dual-monitor setups where your MacBook screen supports True Tone but your external monitor does not. Instead of having two displays with different colour responses throughout the day, Solace creates a consistent warmth schedule that both screens follow simultaneously.

Beyond colour temperature, Solace's schedule can also include:

• Dark mode transitions - switch the entire macOS UI to dark mode at a set time or at actual sunset
• Wallpaper changes - swap wallpapers automatically based on time of day or light/dark mode state
• Weather-aware warmth - optionally adjust colour temperature based on the current weather at your location

All location calculations for sunset timing and weather-based features are performed entirely on-device. Solace does not send your location or usage data to any external server.

Is there a way to get per-monitor True Tone?

Not with software alone. Because True Tone requires physical ambient light sensors in the display and Apple's proprietary display protocol, no macOS app or system setting can add genuine per-monitor True Tone to a third-party display.

There are, however, hardware-level alternatives emerging from monitor manufacturers. BenQ's Mobiuz series includes monitors with built-in ambient light sensors and their own proprietary adaptive backlight system - an independent, hardware-driven approach to the same problem True Tone solves. This is not True Tone and does not integrate with macOS at the software level, but it does provide a real-time sensor-driven colour adaptation at the display hardware layer.

As ambient light sensing becomes more common in premium monitors, hardware-level True Tone equivalents from third-party manufacturers are likely to become more widespread. For now, the practical answer for most Mac users is: use Night Shift or Solace for scheduled software-based warmth, and accept that genuine real-time sensor-driven adaptation requires an Apple display.

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