diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.cpp b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
index d1b0839e8055..c8dbd4320a37 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.cpp
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.cpp
@@ -72,6 +72,7 @@ NS_IMPL_ISUPPORTS1(OfflineCacheUpdateParent,
 //-----------------------------------------------------------------------------
 
 OfflineCacheUpdateParent::OfflineCacheUpdateParent()
+    : mIPCClosed(false)
 {
     // Make sure the service has been initialized
     nsOfflineCacheUpdateService* service =
@@ -87,6 +88,12 @@ OfflineCacheUpdateParent::~OfflineCacheUpdateParent()
     LOG(("OfflineCacheUpdateParent::~OfflineCacheUpdateParent [%p]", this));
 }
 
+void
+OfflineCacheUpdateParent::ActorDestroy(ActorDestroyReason why)
+{
+    mIPCClosed = true;
+}
+
 nsresult
 OfflineCacheUpdateParent::Schedule(const URI& aManifestURI,
                                    const URI& aDocumentURI,
@@ -121,9 +128,9 @@ OfflineCacheUpdateParent::Schedule(const URI& aManifestURI,
     update->AddObserver(this, PR_FALSE);
 
     if (stickDocument) {
-      nsCOMPtr<nsIURI> stickURI;
-      documentURI->Clone(getter_AddRefs(stickURI));
-      update->StickDocument(stickURI);
+        nsCOMPtr<nsIURI> stickURI;
+        documentURI->Clone(getter_AddRefs(stickURI));
+        update->StickDocument(stickURI);
     }
 
     return NS_OK;
@@ -132,6 +139,9 @@ OfflineCacheUpdateParent::Schedule(const URI& aManifestURI,
 NS_IMETHODIMP
 OfflineCacheUpdateParent::UpdateStateChanged(nsIOfflineCacheUpdate *aUpdate, PRUint32 state)
 {
+    if (mIPCClosed)
+        return NS_ERROR_UNEXPECTED;
+
     LOG(("OfflineCacheUpdateParent::StateEvent [%p]", this));
 
     SendNotifyStateEvent(state);
@@ -154,6 +164,9 @@ OfflineCacheUpdateParent::UpdateStateChanged(nsIOfflineCacheUpdate *aUpdate, PRU
 NS_IMETHODIMP
 OfflineCacheUpdateParent::ApplicationCacheAvailable(nsIApplicationCache *aApplicationCache)
 {
+    if (mIPCClosed)
+        return NS_ERROR_UNEXPECTED;
+
     NS_ENSURE_ARG(aApplicationCache);
 
     nsCString cacheClientId;
diff --git a/uriloader/prefetch/OfflineCacheUpdateParent.h b/uriloader/prefetch/OfflineCacheUpdateParent.h
index 247ebdca89c7..bec57d321471 100644
--- a/uriloader/prefetch/OfflineCacheUpdateParent.h
+++ b/uriloader/prefetch/OfflineCacheUpdateParent.h
@@ -62,8 +62,11 @@ class OfflineCacheUpdateParent : public POfflineCacheUpdateParent
     OfflineCacheUpdateParent();
     ~OfflineCacheUpdateParent();
 
+    virtual void ActorDestroy(ActorDestroyReason why);
+
 private:
     void RefcountHitZero();
+    bool mIPCClosed;
 };
 
 }