diff --git a/spine-unity/Assets/Spine/Editor/spine-unity/Editor/Asset Types/AnimationReferenceAssetDrawer.cs b/spine-unity/Assets/Spine/Editor/spine-unity/Editor/Asset Types/AnimationReferenceAssetDrawer.cs
index 2af007b8d..7a769045a 100644
--- a/spine-unity/Assets/Spine/Editor/spine-unity/Editor/Asset Types/AnimationReferenceAssetDrawer.cs	
+++ b/spine-unity/Assets/Spine/Editor/spine-unity/Editor/Asset Types/AnimationReferenceAssetDrawer.cs	
@@ -103,7 +103,7 @@ namespace Spine.Unity.Editor {
 			if (currentAsset != null && currentAsset.SkeletonDataAsset != null) {
 				resolvedSkeletonDataAsset = currentAsset.SkeletonDataAsset;
 				// If other SkeletonDataAsset than expected, use assigned asset but show warning color in Inspector.
-				if (resolvedSkeletonDataAsset != expectedSkeletonDataAsset)
+				if (expectedSkeletonDataAsset && resolvedSkeletonDataAsset != expectedSkeletonDataAsset)
 					skeletonDataAssetMismatch = true;
 			} else {
 				resolvedSkeletonDataAsset = expectedSkeletonDataAsset;
diff --git a/spine-unity/Assets/Spine/package.json b/spine-unity/Assets/Spine/package.json
index f002add0d..81405f800 100644
--- a/spine-unity/Assets/Spine/package.json
+++ b/spine-unity/Assets/Spine/package.json
@@ -2,7 +2,7 @@
 	"name": "com.esotericsoftware.spine.spine-unity",
 	"displayName": "spine-unity Runtime",
 	"description": "This plugin provides the spine-unity runtime core and examples. Spine Examples can be installed via the Samples tab.",
-	"version": "4.3.57",
+	"version": "4.3.58",
 	"unity": "2018.3",
 	"author": {
 		"name": "Esoteric Software",