diff --git a/src/main/java/org/olat/course/nodes/gta/manager/GTAManagerImpl.java b/src/main/java/org/olat/course/nodes/gta/manager/GTAManagerImpl.java
index 4cff45ab731b68fde8b3860956b5dd0c6691e118..a02af7b79456e7996cc25e98faf927cb06dbb601 100644
--- a/src/main/java/org/olat/course/nodes/gta/manager/GTAManagerImpl.java
+++ b/src/main/java/org/olat/course/nodes/gta/manager/GTAManagerImpl.java
@@ -687,7 +687,9 @@ public class GTAManagerImpl implements GTAManager, DeletableGroupData {
 		
 		if(nextSlot == null) {
 			//begin a new round
-			nextSlot = slots[0];
+			if (slots.length > 0) {
+				nextSlot = slots[0];
+			}
 		}
 		return nextSlot;
 	}