diff --git a/scm-webapp/src/main/java/sonia/scm/api/rest/resources/RepositoryResource.java b/scm-webapp/src/main/java/sonia/scm/api/rest/resources/RepositoryResource.java
index 5766224784..95873dbd2d 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/rest/resources/RepositoryResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/rest/resources/RepositoryResource.java
@@ -415,9 +415,12 @@ public class RepositoryResource
         {
           ChangesetPreProcessor cpp = factory.createPreProcessor(repository);
 
-          for (Changeset c : changesets.getChangesets())
+          if (cpp != null)
           {
-            cpp.process(c);
+            for (Changeset c : changesets.getChangesets())
+            {
+              cpp.process(c);
+            }
           }
         }
       }