diff --git a/smtk/mesh/xms/operators/GenerateMesh.sbt b/smtk/mesh/xms/operators/GenerateMesh.sbt
index c2557ad9ad4aad178f7458d43049ce471794b3b7..bd11398d66a659c520af6effa66e2baabfd40630 100644
--- a/smtk/mesh/xms/operators/GenerateMesh.sbt
+++ b/smtk/mesh/xms/operators/GenerateMesh.sbt
@@ -8,7 +8,7 @@
       <BriefDescription>
         Generate a mesh from a model.
       </BriefDescription>
-      <AssociationsDef Name="model" NumberOfRequiredValues="1">
+      <AssociationsDef Name="model" NumberOfRequiredValues="1" LockType="Read">
         <MembershipMask>model</MembershipMask>
         <BriefDescription>The model to mesh</BriefDescription>
       </AssociationsDef>