diff --git a/etc/xsd/TPD.xsd b/etc/xsd/TPD.xsd
index 3a8704a46d61b961aa5481b56b4b17701aa78305..545a9cd6e5c591af673e22400294c298390b1d87 100644
--- a/etc/xsd/TPD.xsd
+++ b/etc/xsd/TPD.xsd
@@ -435,7 +435,7 @@
 			  <xs:element name="ReferencedProject" minOccurs="0" maxOccurs="unbounded">
 				<xs:complexType>
 					<xs:attribute name="name" type="xs:normalizedString" use="required" />
-					<xs:attribute name="projectLocationURI" type="xs:normalizedString" use="required" />
+					<xs:attribute name="projectLocationURI" type="xs:normalizedString" use="optional" />
 					<xs:attribute name="tpdName" type="xs:normalizedString" use="optional" />
 				</xs:complexType>
 			  </xs:element>