diff --git a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/MetaDataBuilder.java b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/MetaDataBuilder.java
index 0c44aa65a526506b32ea3d7827224d77c6706f77..fc8934a5f1248113f3c1313de8f5dc017e4ce025 100644
--- a/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/MetaDataBuilder.java
+++ b/datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/MetaDataBuilder.java
@@ -173,6 +173,10 @@ public class MetaDataBuilder
 
     private void addProperties(String category, List<IEntityProperty> properties)
     {
+        if (properties == null)
+        {
+            return;
+        }
         Collections.sort(properties, PROPERTIES_COMPARATOR);
         for (IEntityProperty property : properties)
         {