=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/organisationunit/OrganisationUnit.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/organisationunit/OrganisationUnit.java	2015-11-21 15:52:48 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/organisationunit/OrganisationUnit.java	2015-12-01 10:00:42 +0000
@@ -258,8 +258,8 @@
         Set<DataSet> toRemove = Sets.difference( dataSets, updates );
         Set<DataSet> toAdd = Sets.difference( updates, dataSets );
 
-        toRemove.parallelStream().forEach( d -> d.getSources().remove( this ) );
-        toAdd.parallelStream().forEach( d -> d.getSources().add( this ) );
+        toRemove.stream().forEach( d -> d.getSources().remove( this ) );
+        toAdd.stream().forEach( d -> d.getSources().add( this ) );
 
         dataSets.clear();
         dataSets.addAll( updates );