If you want to uninstall Lunar completely:

Using brew:

brew uninstall --cask --force --zap lunar 

Using LaunchPad:

• Open Launchpad from the Dock or Spotlight
• Type Lunar to find the app
• Hold the ⌥ option key and click on the x button

If you only want to make sure Lunar is not running:

• Disable Launch at login
• Quit Lunar

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The app does not have any daemons or background services.

This is usually caused by either a bug in monitor firmware or a faulty color profile.

Try using a different Colour Profile.

Lunar can't cause any hardware damage, so if the monitor didn't have a hidden problem before, the issue should be fixable.

On very rare conditions, the MacBook screen can get into a state where it shows a black screen and you can't see the login screen because of a color profile issue.

Possible solutions

1. If you have access to another monitor, open a Terminal and run the following commands:

sudo rm /Library/Preferences/com.apple.windowserver.displays.plist sudo rm /Library/ColorSync/Profiles/Displays/* rm ~/Library/Preferences/ByHost/com.apple.windowserver*.plist sudo nvram -c 

Then restart the MacBook.

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2. If you only have the MacBook screen:

• shut down the Macbook
• boot into recovery mode by holding the power button (on Apple Silicon) or ⌘ Command + R while booting (on Intel Macs)
• open Disk Utility and mount the Data volume then close Disk Utility
• open a Terminal in recovery mode by going to the Utilities menu at the top and selecting Terminal
• run the following commands to reset the color profile to the default one:

rm /Volumes/*/Library/Preferences/com.apple.windowserver.displays.plist rm /Volumes/*/Library/ColorSync/Profiles/Displays/* rm /Volumes/*/Users/*/Library/Preferences/ByHost/com.apple.windowserver*.plist sudo nvram -c 

Then restart the MacBook.

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3. Try to login using VoiceOver:

• Restart the computer to get to the login screen
  • Hold the power button until the MacBook turns off
  • Press the power button again to turn it on
  • Wait about 10 seconds to make sure you got to the login screen, even if you can't see it
• Press ⌘ Command + F5 to enable VoiceOver
• Press Volume Up once or twice to make sure the volume is not muted
• If the voice over says username press Enter or Tab to get into the password field
• If the voice over says password, type your password and press Enter

The MacBook screen should be back to normal after you login.

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Technical explanation

This is a problem in the system color profile logic and it can happen with or without Lunar.

It can be aggravated by Lunar's use of Gamma tables because the dimming might get the color formula into a state where all the computed colors are 0 or black, if the color profile used can't cover the full range of colors.

It can also happen when Lunar activates XDR Brightness or Full Range on a MacBook screen in very specific scenarios that we haven't identified yet.

First thing to try

1. Quit Lunar
2. Unplug the monitor from the power socket
3. Plug the monitor back

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Possible causes

Color Profiles

Because of a macOS bug in the Gamma API, your screen can go black then get back to normal after a few seconds.

There's no complete fix for this as it is a macOS bug, but you can lower the chances of it appearing using the following steps:

• Use a default color profile in System Preferences -> Displays
• Minimise future Gamma resets by disabling the HDR compatibility workaround from HDR Settings

If that doesn't fix the issue, you can try to disable the usage of Gamma completely from Advanced Settings

Technical explanation

This usually happens when custom color profiles are used, but it was reported on some default monitor profiles as well.

The bug is usually triggered when Lunar tries to reset the gamma tables to their default values by calling the CGDisplayRestoreColorSyncSettings() system method.

This should be a completely normal use case, and the call should simply do nothing if the gamma tables are already at their default values. But for unknown reasons, this API call will sometimes set all RGB Gamma tables to 0 and all colors will show up as black.

The flash you see comes from Lunar detecting this zero-gamma problem in the background, and applying a default Gamma table forcefully to avoid being stuck with a blacked out display.

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Firmware bugs

Some monitors have firmware bugs and don't react well to DDC commands.

You can try to open Advanced Settings and enable the Delay DDC after wake experimental setting:

If the problem persists, you will need to disable DDC completely.

To do that, disable Hardware (DDC) controls from the Controls menu:

Lunar will fallback to adjusting brightness and contrast in software using Gamma values.

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Notes about Gamma:

• Conflicts with other apps that use Gamma like f.lux so you have to quit them
  • Night Shift is a good alternative as it doesn't use Gamma
• Can only lower the brightness, not increase it
  • That's why you have to manually set the monitor brightness and contrast to maximum using its physical buttons
• Can't change the volume or input of the monitor
  • Those features require DDC

This is either a macOS or a monitor problem, and it happens for a small number of people.

Brightness might be working fine until the Mac/monitor enters standby, then after wake you might see the lock icon.

This is caused by the DDC port for the monitor not being visible anymore inside the macOS I/O Registry tree.

Unfortunately the only way to fix it is to restart Lunar so it can get a new refreshed view of the I/O Registry.

I have added an instant Restart hotkey on the Hotkeys page of the Lunar preferences window, to allow for a faster recovery when this happens.

Some monitors don't accept DDC commands (which Lunar uses to control brightness and volume).

Below are some possible causes for this issue.

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Built-in HDMI port of the 2018 Mac Mini

The HDMI port of these devices is blocking DDC requests without a known cause.

Using one of the Thunderbolt ports usually fixes this (through USB-C-to-HDMI cable, Thunderbolt hub, etc.).

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HDMI-to-USB-C Cables

Some users report that DDC controls are blocked on specific monitors when using HDMI to USB-C cables and that switching to DisplayPort fixes their problem.

If possible, try a DisplayPort to USB-C cable.

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Samsung M7, M9, G7, G9 on USB-C

DDC seems to only work through the HDMI port of these monitors. The USB-C connection blocks hardware brightness/volume control.

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Smart Monitors

In most cases, DDC is blocked by a monitor setting that tries to take complete control of Brightness, Contrast or Volume.

Usually disabling those functions in the monitor settings will allow Lunar control brightness.

Below are some settings that are known to block DDC, grouped by monitor vendor.

Samsung

• Disable Input Signal Plus
• Disable Magic Bright
• Disable Eye Saver Mode
• Disable Eco Saving Plus
• Disable Smart ECO Saving
• Disable PIP/PBP Mode
• Disable Dynamic Brightness

Dell

• Disable Uniformity Compensation
• Set Preset Mode to Custom or Standard to allow DDC

LG

• Disable Uniformity
• Disable Auto Brightness
• Set Picture Mode to Custom or Standard to allow DDC

BenQ

• Disable Bright Intelligence
• Disable Bright Intelligence Plus or B.I.+
• Set Picture Mode to Standard

Lenovo

• Disable Local Dimming
• Disable HDR
• Disable Dynamic Contrast
• Set Color Mode Custom
• Set Scenario Modes to Panel Native

Xiaomi Mi Monitor

• Disable Dynamic Brightness
• Set Smart Mode to Standard

PRISM

• Set On-the-Fly Mode to Standard to allow DDC

Others

• Disable Ambient Light Sensing
• Disable Dual DisplayPort
• Set Dynamic Picture Mode to Custom or Standard to allow DDC
• Set Color Presets to Custom or Standard to allow DDC

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DDC blockers

Other cases where DDC will not work:

• TV working as monitor
  • TVs don't support the VESA Monitor Control Command Set which is needed for sending DDC requests
• DisplayLink
  • DisplayLink uses proprietary drivers and while it has support for DDC, that functionality is not provided on macOS
  • Lunar can control DisplayLink monitors using the Network Control feature
• HDMI port of the 2018 Mac Mini
  • The HDMI port of these devices is blocking DDC requests without a known cause
  • Using the Thunderbolt connector fixes this (through USB-C-to-HDMI cable, Thunderbolt hub, etc.)
• Non-compliant hub/dock/adapter
  • This is the most common issue and it can't be fixed in software
  • Because most new Macs only have USB-C ports, most users use some kind of Thunderbolt hub or dock
  • A lot of these hubs block DDC requests completely,
  • If the hub supports more than one monitor, it usually forwards DDC requests to only one of them
  • Here are some of the hubs that are known to work:
    • Baseus HDMI, USB-C PD, 3 USB-A
    • Baseus HDMI, USB-C PD, 3 USB-A + Ethernet
    • Baseus HDMI, USB-C PD, 3 USB-A + Ethernet + SD/microSD reader

If Lunar doesn't fallback automatically to a working control mode, you can manually disable Hardware (DDC) controls from the Controls menu:

Lunar will fallback to adjusting brightness and contrast in software using Gamma values.

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Notes about Gamma:

• Conflicts with other apps that use Gamma like f.lux so you have to quit them
  • Night Shift is a good alternative as it doesn't use Gamma
• Can only lower the brightness, not increase it
  • That's why you have to manually set the monitor brightness and contrast to maximum using its physical buttons
• Can't change the volume or input of the monitor
  • Those features require DDC

The active monitor hotkey behaviour was changed because a lot of users requested it.

Basically, Ctrl+Brightness is now the way to control the external monitor as that is also how macOS works natively with Ultrafine and Thunderbolt monitors.

You can still go back to the old behaviour (mostly) by setting the Brightness keys adjust in other modes dropdown to Display with cursor:

Lunar does not change colors in its default configuration. The app only sends brightness and contrast commands.

The problem is most likely that the monitor is reacting to those commands by switching to a custom color profile and affecting how the colors appear.

You can try locking the contrast to see if the monitor starts behaving correctly:

If that doesn't fix the issue, it means that your monitor doesn't accept brightness control on the color profile you have chosen. There's nothing we can do to fix this as the problem is inside the monitor firmware.

The EEPROM write limit

It is commonly believed that DDC commands will lower the lifetime of a monitor because the brightness values need to be stored in the EEPROM memory of the monitor and EEPROMs have a limited number of write cycles (usually around 100000).

I can't be certain for all monitor models, but I'm pretty sure this is no longer a real problem.

I've tested millions of writes on my LG 27UD88 and the monitor eventually failed because of the backlight controller chip. The memory chip was still working after 5 years of testing Lunar far more than what an average user would do in 15 years of usage.

Modern monitor chips

Most monitors use flash memory instead of EEPROM nowadays, and they also have RAM which can cache the DDC values without any write cycle limit, and only set them persistently in the flash after specific events.

For example my LG monitor was similar to this one from the iFixit teardown: LG 25UM58-P Teardown

It has a Novatek NT68 chip whose datasheet mentions the following:

• 128 Kbytes of on-chip flash memory for program memory
• 512 Bytes RAM Buffer for hardware DDC Port

So when doing a lot of DDC writes, like what Lunar does with smooth brightness transitions, those values will be stored in RAM, and won't affect the EEPROM write cycles.

The maximum brightness value is adapted by the macOS system based on the ambient light around you, Lunar simply reports that value directly.

If you flash a bright light on the MacBook's light sensor, you will see the brightness value go up to the real maximum nits.

To disable this behaviour, you can disable Automatically adjust brightness from the System Settings:

Yes, it is mostly safe. The MacBook and Pro Display XDR have been designed to sustain higher than 500nits of brightness.

1. macOS has a hard limit on the LED temperature and it will start lowering brightness forcefully way before it can do any damage
2. If used with mostly non-white backgrounds/apps, only the really close-to-white pixels will actually reach 1600 nits, while the rest will hover below 1000 nits, so they'll have plenty of time to cool down

While sifting through macOS internals, I've discovered a lot of logic for temperature thresholds, local dimming zones to keep pixels at their most efficient brightness, and safe measures for high power usage.

Based on the current knowledge, I'd say this is pretty safe to use, given that the system will not allow you to go past unsafe limits.

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LED lifespan

Yes, the lifespan of the LEDs will be lowered if XDR Brightness is used daily, but no one can say by how much.

That's just how LEDs work.

Heat degrades the junction between the semiconductors, causing less of the electrical current to be converted to light which will make LEDs dimmer over time.

How are LEDs affected by heat?

macOS will stop XDR when the heat passes a threshold, but if you find that the warning icon (⚠️) appears often in the menu bar you might want to use higher brightness less often, or consider using Dark Mode.

Light text on dark backgrounds will keep the LEDs much cooler for longer periods of time, while still improving readability.

The new Full Range mode is now the successor of XDR Brightness and is preferred because it removes most of the limitations that XDR had, like:

• It doesn't clip colors in HDR content
• The system adaptive brightness keeps working and uses the full range
• There's no lag when going from SDR to XDR brightness
• Can be kept on all the time without any downsides
• Can work in tandem with f.lux or other color management tools

Some downsides of Full Range:

• It only works on MacBook Pro XDR screens (can't be used on external monitors)
• The screen will flash one or two times when toggling Full Range

The system will still adapt the maximum nits of brightness based on the ambient light, so you might get a max of 800 nits in a dark room and 1600 nits in sunlight.

Disabling the system adaptive brightness will turn off this behaviour.

Sub-zero Dimming needs the range between 0% and 1% to be reserved for Lunar, otherwise when you get from 1% to 0%, the display will just turn off.

Make sure the Min Brightness of the MacBook screen is set to 1 or higher in Display Settings:

Perfectly safe.

Sub-zero dimming darkens the colours in software after the lowest possible native brightness has been reached.

This can't cause any damage. It is equivalent to having dark colored or black pixels on the screen which is completely normal.

Lunar needs Accessibility permissions to listen for Media Keys (brightness and volume).

To make sure the permissions are enabled, launch System Preferences->Security & Privacy and check if Lunar is present and enabled in the Accessibility list.

If it is, try removing it and re-adding it just be sure it isn't a code signing issue.

If the keys still don't work, it's possible that:

• the F14/F15 as brightness keys option is disabled and the keyboard used doesn't send brightness key events
  • enable the option on the Hotkeys page to allow Lunar to listen for default brightness key events
• the system permissions database is corrupted
  • Launch Terminal.app and run the following command: /usr/bin/tccutil reset All fyi.lunar.Lunar
  • Reboot the system, launch Lunar again, then give Lunar permissions when it asks
• your monitor doesn't support brightness/volume control

To check why brightness doesn't work, try running diagnostics by clicking on Open Lunar Diagnostics from the Lunar menu.

These are some of the cases where volume control is not available:

• If you see Software Control under your monitor name in Lunar
• If DDC is not responsive because of a non-compliant hub/dock/adapter (Lunar should prompt you about that)
  • In this case you could try a different way to connect the monitor to your Mac

Yes, there's a hidden Round Corners setting on the built-in page.

Hover your mouse above the Auto Blackout button to make the setting appear, then scroll to change the setting:

Lunar needs Accessibility permissions to know where the windows of an app are placed.

To make sure the permissions are enabled, launch System Preferences->Security & Privacy and check if Lunar is present and enabled in the Accessibility list.

If it is, try removing it and re-adding it just be sure it isn't a code signing issue.

If offsets still don't work, it's possible that the system permissions database is corrupted (see fix here)

Unfortunately most monitors don't offer a way to hide their volume indicator OSD.

But Lunar offers a way to hide the macOS volume OSD so that at least you can see only one volume indicator.

Toggle the macOS Volume OSD setting to Hide inside the Lunar DDC menu

These are system settings and are not honored by any macOS app

Lunar (and all other apps) have to listen for brightness keys explicitly and the above settings don't have any effect on apps.

To disable Lunar's own media keys listener, uncheck F14/F15 as brightness keys on the Hotkeys page.

Note: not all keyboards have brightness keys that send non-F14/F15 key events.

Re-check the checkbox if brightness keys stop working after unchecking it.

Corrupted permissions database

First thing to try is to reset the System's permissions database.

Launch Terminal.app and run the following command:

Note: to run a command, paste the text in the Terminal and press Enter after that

/usr/bin/tccutil reset All fyi.lunar.Lunar

Then reboot the system and launch Lunar again.

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If you get a message saying you don't have permissions to do the above, you can try resetting all permissions:

/usr/bin/tccutil reset All

Note: This will reset the permissions for all apps on the system.

And as a last resort, you can delete the whole permissions database using the following steps:

1. Open Finder
2. Go to /Library/Application Support/com.apple.TCC
3. Find TCC.db and move it to Trash

Then reboot the system and launch Lunar again.

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Wrong app location

Where Lunar is launched from matters.

If you, for example, launched Lunar from Downloads and gave it permissions then, and then you moved it to Applications, then those permissions are not valid.

The macOS system stores permissions based on path and code signature.

You have to manually remove Lunar from the Accessibility list and add it again from the path you always launch it.