diff --git a/solr/contrib/dataimporthandler/build.xml b/solr/contrib/dataimporthandler/build.xml
index e686643476e..991337e4ce1 100644
--- a/solr/contrib/dataimporthandler/build.xml
+++ b/solr/contrib/dataimporthandler/build.xml
@@ -23,6 +23,9 @@
     Data Import Handler
   </description>
 
+  <!-- the tests have some parallel problems: writability to single copy of dataimport.properties -->
+  <property name="tests.threadspercpu" value="0"/>
+
   <import file="../contrib-build.xml"/>
 
 </project>