Unity-Technologies/UnityCsReference · error · ArgumentNullException

Value for parameter atlases is null

Error message

Value for parameter atlases is null

What it means

Thrown by SpriteAtlasUtility.PackAtlases when the atlases array argument is null. PackAtlases packs a caller-supplied set of SpriteAtlas assets into textures via the native PackAtlasesInternal; before delegating it asserts the array exists. ArgumentNullException is used because the whole parameter (not just an element) is missing, so there is nothing to iterate.

Source

Thrown at Editor/Mono/2D/SpriteAtlas/EditorSpriteAtlas.bindings.cs:28

using UnityEditor.AssetImporters;
using UnityEngine.UIElements;

namespace UnityEditor.U2D
{
    [NativeHeader("Runtime/2D/SpriteAtlas/SpriteAtlas.h")]
    [NativeHeader("Editor/Src/2D/SpriteAtlas/SpriteAtlasPackingUtilities.h")]
    public class SpriteAtlasUtility
    {
        [FreeFunction("CollectAllSpriteAtlasesAndPack")]
        extern public static void PackAllAtlases(BuildTarget target, bool canCancel = true);

        [FreeFunction("PackSpriteAtlases")]
        extern internal static void PackAtlasesInternal(SpriteAtlas[] atlases, BuildTarget target, bool canCancel = true, bool invokedFromImporter = false, bool unloadSprites = false);

        public static void PackAtlases(SpriteAtlas[] atlases, BuildTarget target, bool canCancel = true)
        {
            if (atlases == null)
                throw new ArgumentNullException("atlases", "Value for parameter atlases is null");
            foreach (var atlas in atlases)
                if (atlas == null)
                    throw new ArgumentNullException("atlases", "One of the elements in atlases is null. Please check your Inputs.");
            PackAtlasesInternal(atlases, target, canCancel, false, true);
        }

        [FreeFunction("GetSpriteTexture")]
        extern internal static Texture2D GetSpriteTexture([NotNull] Sprite sprite, bool fromAtlas);

        [FreeFunction("SpriteAtlasExtensions::CleanupAtlasPacking")]
        extern public static void CleanupAtlasPacking();

        [FreeFunction("SpriteAtlasExtensions::OnSpriteAtlasSettingsChanged")]
        extern internal static void OnSpriteAtlasSettingsChanged();
    }


    [StructLayout(LayoutKind.Sequential)]

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. Initialize atlases via AssetDatabase.FindAssets("t:SpriteAtlas") and LoadAssetAtPath before calling PackAtlases.
2. Guard with 'if (atlases == null || atlases.Length == 0) return;' for optional-pack workflows.
3. Log a clear message and skip when the selection/gather step yields null instead of forwarding it.
4. Verify the array is populated in the same scope that creates it, not in a deferred callback.

Example fix

// before
SpriteAtlasUtility.PackAtlases(null, BuildTarget.StandaloneWindows64);

// after
var guids = AssetDatabase.FindAssets("t:SpriteAtlas");
var atlases = guids.Select(g => AssetDatabase.LoadAssetAtPath<SpriteAtlas>(AssetDatabase.GUIDToAssetPath(g))).ToArray();
if (atlases == null || atlases.Length == 0) { Debug.LogWarning("No sprite atlases found; skipping pack."); return; }
SpriteAtlasUtility.PackAtlases(atlases, BuildTarget.StandaloneWindows64);

if (atlases == null) { Debug.LogWarning("atlases is null; nothing to pack."); return; }

static bool HasAtlases(SpriteAtlas[] a) => a != null && a.Length > 0;

When it happens

Trigger: Calling SpriteAtlasUtility.PackAtlases(null, target). Passing a field/property that was never assigned (e.g. a SerializedProperty.objectReferenceValue-derived array that came back null). Forwarding the result of FindObjectsByType or AssetDatabase.FindAssets that returned nothing and got coerced to null.

Common situations: Editor build scripts and CI batch packing pipelines that gather atlases dynamically. PostImport or BuildPlayer callbacks that pack atlases where asset loading failed silently. Menu-item automation where the user forgot to select atlases in the Project window.

Related errors

• One of the elements in atlases is null. Please check your In
• Parameter asset is null
• gameObject
• bindings must be non-null
• keyframes must be non-null

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/17649806846e1d27. Report an issue: GitHub.