diff --git a/src/main/java/caosdb/datetime/UTCDateTime.java b/src/main/java/caosdb/datetime/UTCDateTime.java
index 846c8f9f266d4b834314b95e00973993d9031224..886080dd48718bcfdc9f2f8d032dd35b624671c7 100644
--- a/src/main/java/caosdb/datetime/UTCDateTime.java
+++ b/src/main/java/caosdb/datetime/UTCDateTime.java
@@ -292,7 +292,7 @@ public class UTCDateTime implements Interval {
 
   @Override
   public String toString() {
-    throw new NullPointerException("toString method!!!");
+    return toDateTimeString(TimeZone.getDefault());
   }
 
   public static UTCDateTime UTCSeconds(final Long utcseconds, final Integer nanosecond) {