diff --git a/src/main/java/org/olat/course/run/navigation/NavigationHandler.java b/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
index d22a948cc8ef63fcfe4a9e598218d5a4ab4949d3..5c827789e4e2ea32da4c9960acd057d8ceb471d8 100644
--- a/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
+++ b/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
@@ -143,7 +143,7 @@ public class NavigationHandler implements Disposable {
 		String treeNodeId = treeEvent.getNodeId();
 		TreeNode selTN = treeModel.getNodeById(treeNodeId);
 		if (selTN == null) {
-			throw new AssertException("no treenode found:" + treeNodeId);
+			selTN = treeModel.getRootNode();
 		}
 
 		// check if appropriate for subtreemodelhandler