diff --git a/src/main/java/org/olat/course/MergedCourseContainer.java b/src/main/java/org/olat/course/MergedCourseContainer.java
index 14be0d5958c7c34bb3929c6294cf5ebbd89b25e8..f6a24e1e1456c48d1681a7e44bff28453e4f7192 100644
--- a/src/main/java/org/olat/course/MergedCourseContainer.java
+++ b/src/main/java/org/olat/course/MergedCourseContainer.java
@@ -123,6 +123,8 @@ public class MergedCourseContainer extends MergeSource {
 	}
 	
 	private void addFolderBuildingBlocks(PersistingCourseImpl course, MergeSource nodesContainer, TreeNode courseNode) {
+		if(courseNode == null) return;
+		
 		for (int i = 0; i < courseNode.getChildCount(); i++) {
 			TreeNode child = (TreeNode)courseNode.getChildAt(i);