diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/server/EntityExistenceChecker.java b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/server/EntityExistenceChecker.java
index e3953649aeb154ea765881bdc07336a0c1eb7dc6..0301841573ac7da1051fd30f5fa86c949bb91aed 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/server/EntityExistenceChecker.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/plugin/generic/server/EntityExistenceChecker.java
@@ -357,9 +357,14 @@ class EntityExistenceChecker
             {
                 String value = property.getValue();
                 MaterialTypePE materialType = propertyTypePE.getMaterialType();
-                MaterialIdentifier materialIdentifier =
-                        new MaterialIdentifier(value, materialType.getCode());
-                materialExistenceManager.exists(materialIdentifier);
+                if (materialType != null) // if material type is null, it means, the property is of
+                                          // "any material type", so we don't need to check if it
+                                          // exist
+                {
+                    MaterialIdentifier materialIdentifier =
+                            new MaterialIdentifier(value, materialType.getCode());
+                    materialExistenceManager.exists(materialIdentifier);
+                }
             }
         }
     }