Copy over all UV channels.

The duplicate function now copies all 8 UV channels. So your lightmap UV's don't get lost!

.vscode/launch.json

@@ -0,0 +1,54 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Unity Editor",
+            "type": "unity",
+            "path": "/D:/PerforceMax/Projects/Unity/MA_TextureAtlasser/Library/EditorInstance.json",
+            "request": "launch"
+        },
+        {
+            "name": "Windows Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "OSX Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "Linux Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "iOS Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "Android Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "Xbox One Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "PS4 Player",
+            "type": "unity",
+            "request": "launch"
+        },
+        {
+            "name": "SwitchPlayer",
+            "type": "unity",
+            "request": "launch"
+        }
+    ]
+}

Assets/MA_ToolBox/MA_Utilities/MeshUtils/MA_MeshUtils.cs

@@ -84,7 +84,12 @@ public static Mesh MA_DuplicateMesh(Mesh mesh)
 				newMesh.SetTriangles(mesh.GetTriangles(i), i);
 			}
 			newMesh.SetNormals(new List<Vector3>(mesh.normals));
-			newMesh.SetUVs(0, new List<Vector2>(mesh.uv));
+			for (int i = 0; i < 8; i++)
+			{
+				List<Vector2> uvs = new List<Vector2>();
+				mesh.GetUVs(i, uvs);
+				newMesh.SetUVs(i, uvs);
+			}
 			newMesh.SetTangents(new List<Vector4>(mesh.tangents));
 			newMesh.SetColors(new List<Color>(mesh.colors));