Unity-Technologies/UnityCsReference · error · Exception

Lightmapping.lightingSettings is null. Please assign it to a

Error message

Lightmapping.lightingSettings is null. Please assign it to an existing asset or a new instance.

What it means

Lightmapping.lightingSettings getter throws a plain System.Exception when the backing LightingSettings asset is null. Rather than returning null, Unity forces callers to assign a LightingSettings instance (a new one or an existing asset) before reading the active settings. A non-throwing TryGetLightingSettings(out var) overload exists for code paths that may run before settings exist.

Source

Thrown at Editor/Mono/GI/Lightmapping.bindings.cs:539

        [StaticAccessor("GetLightmapSettings().GetReadOnlySharedData()")]
        public static extern bool HasDynamicGILightmapTextures();

        public static bool TryGetLightingSettings(out LightingSettings settings)
        {
            settings = lightingSettingsInternal;

            return (settings != null);
        }

        public static LightingSettings lightingSettings
        {
            get
            {
                var settings = lightingSettingsInternal;

                if (settings == null)
                {
                    throw new Exception("Lightmapping.lightingSettings is null. Please assign it to an existing asset or a new instance. ");
                }

                return settings;
            }
            set
            {
                lightingSettingsInternal = value;
            }
        }

        [StaticAccessor("GetLightmapSettings()")]
        [NativeName("LightingSettings")]
        internal static extern LightingSettings lightingSettingsInternal { get; set; }

        [StaticAccessor("GetLightmapSettings()")]
        [NativeName("LightingSettingsDefaults_Scripting")]
        public static extern LightingSettings lightingSettingsDefaults { get; }

View on GitHub (pinned to 225b0fbdb5)

Solutions

Assign settings first: Lightmapping.lightingSettings = new LightingSettings(); (or an existing asset).
Use the non-throwing overload: if (Lightmapping.TryGetLightingSettings(out var s)) { ... } else { s = new LightingSettings(); Lightmapping.lightingSettings = s; }
Ensure the scene's referenced LightingSettings asset is not deleted/null.

Example fix

// before
var s = Lightmapping.lightingSettings;
// after
if (!Lightmapping.TryGetLightingSettings(out var s))
{
    s = new LightingSettings();
    Lightmapping.lightingSettings = s;
}

Defensive patterns

Strategy: validation

Validate before calling

LightingSettings s;
if (Lightmapping.TryGetLightingSettings(out s))
{
    // use s
}
else
{
    s = new LightingSettings();
    Lightmapping.lightingSettings = s;
}

Try / catch

try { var s = Lightmapping.lightingSettings; }
catch (System.Exception) { Lightmapping.lightingSettings = new LightingSettings(); }

Prevention

Prefer TryGetLightingSettings over the throwing getter in code that may run before settings exist.
Always assign a LightingSettings in bake automation/CI before reading it.
Do not delete the LightingSettings asset a scene references.

When it happens

Trigger: Reading Lightmapping.lightingSettings in a fresh scene/project with no lighting settings asset; after the LightingSettings asset was deleted or cleared; in batchmode/headless bake automation that never assigned one.

Common situations: New scene before any lighting settings were generated; deleted the LightingSettings asset from disk; CI bake script that jumps straight to reading settings.

Related errors

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/1c7c1a5358b2e296. Report an issue: GitHub.