diff --git a/core/src/main/java/hudson/tasks/MailSender.java b/core/src/main/java/hudson/tasks/MailSender.java
index 4fb5b730710576fae3fd5e95ede89516e6ac2815..ccd90976590efe8d01da85afb9ba3812867ff00b 100644
--- a/core/src/main/java/hudson/tasks/MailSender.java
+++ b/core/src/main/java/hudson/tasks/MailSender.java
@@ -252,7 +252,7 @@ public class MailSender<P extends AbstractProject<P, B>, B extends AbstractBuild
             for (Entry change : build.getChangeSet()) {
                 User a = change.getAuthor();
                 if (users.add(a)) {
-                    String adrs = a.getProperty(Mailer.UserProperty.class).getAddress();
+                    String adrs = Util.fixEmpty(a.getProperty(Mailer.UserProperty.class).getAddress());
                     if(debug)
                         listener.getLogger().println("  User "+a.getId()+" -> "+adrs);
                     if (adrs != null)