diff --git a/VectoCore/VectoCore/Resources/XSD/VectoOutputCustomer.0.9.xsd b/VectoCore/VectoCore/Resources/XSD/VectoOutputCustomer.0.9.xsd
index 9b4b2bbc364864e708fbe64e0fe81e47d4fb0bc3..027ed8126cfa67fea6dee32bff520379250b78ab 100644
--- a/VectoCore/VectoCore/Resources/XSD/VectoOutputCustomer.0.9.xsd
+++ b/VectoCore/VectoCore/Resources/XSD/VectoOutputCustomer.0.9.xsd
@@ -1467,7 +1467,7 @@
 			<xs:choice>
 				<xs:sequence>
 					<xs:element name="Result" type="AbstractResultType" maxOccurs="unbounded"/>
-					<xs:element name="Summary" type="AbstractResultSummaryType"/>
+					<xs:element name="Summary" type="AbstractResultSummaryType" minOccurs="0"/>
 				</xs:sequence>
 				<xs:element name="ExemptedVehicle">
 					<xs:complexType/>