diff --git a/changelog.html b/changelog.html
index 64eec757a4..bf60274fdd 100644
--- a/changelog.html
+++ b/changelog.html
@@ -62,6 +62,9 @@ Upcoming changes</a>
   <li class=bug>
     <code>/computer/*/doDelete</code> should try harder to remove even “zombie” <code>Computer</code>s.
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-15369">issue 15369</a>)
+  <li class=bug>
+    NPE from <code>PluginManager</code>.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-15511">issue 15511</a>)
   <li class=rfe>
     Added "manage old data" permanently to the "manage Jenkins" page.
   <li class=rfe>
diff --git a/core/src/main/java/hudson/PluginManager.java b/core/src/main/java/hudson/PluginManager.java
index b6c2ac2ab2..12fa0bcb16 100644
--- a/core/src/main/java/hudson/PluginManager.java
+++ b/core/src/main/java/hudson/PluginManager.java
@@ -345,6 +345,9 @@ public abstract class PluginManager extends AbstractModelObject implements OnMas
                     for (final PluginWrapper p : activePlugins.toArray(new PluginWrapper[activePlugins.size()])) {
                         g.followedBy().notFatal().attains(PLUGINS_STARTED).add("Initializing plugin " + p.getShortName(), new Executable() {
                             public void run(Reactor session) throws Exception {
+                                if (!activePlugins.contains(p)) {
+                                    return;
+                                }
                                 try {
                                     p.getPlugin().postInitialize();
                                 } catch (Exception e) {