diff --git a/src/main/java/org/olat/core/commons/services/taskexecutor/model/PersistentTaskRunnable.java b/src/main/java/org/olat/core/commons/services/taskexecutor/model/PersistentTaskRunnable.java
index 02eb8088d765309d8151a8f317808bd041fb1553..be859a618ad72accbdef3fc49c17a3a774da1114 100644
--- a/src/main/java/org/olat/core/commons/services/taskexecutor/model/PersistentTaskRunnable.java
+++ b/src/main/java/org/olat/core/commons/services/taskexecutor/model/PersistentTaskRunnable.java
@@ -57,7 +57,7 @@ public class PersistentTaskRunnable implements Runnable {
 		} catch (Throwable e) {
 			DBFactory.getInstance().rollbackAndCloseSession();
 			markAsFailed(task);
-			log.error("Error while running task in a separate thread: " + task.getKey(), e);
+			log.error("Error while running task in a separate thread: " + (task == null ? "NULL" : task.getKey()), e);
 		}
 	}