diff --git a/core/src/main/groovy/com/muwire/core/messenger/Messenger.groovy b/core/src/main/groovy/com/muwire/core/messenger/Messenger.groovy
index 7737c4d8..b254e995 100644
--- a/core/src/main/groovy/com/muwire/core/messenger/Messenger.groovy
+++ b/core/src/main/groovy/com/muwire/core/messenger/Messenger.groovy
@@ -180,12 +180,13 @@ class Messenger {
     }
     
     public synchronized void onMessageReceivedEvent(MessageReceivedEvent e) {
-        inboxMessages.add(e.message)
-        diskIO.execute({
-            File unread = new File(inbox, deriveUnread(e.message))
-            unread.createNewFile()
-            persist(e.message, inbox)
-        })
+        if (inboxMessages.add(e.message)) {
+            diskIO.execute({
+                File unread = new File(inbox, deriveUnread(e.message))
+                unread.createNewFile()
+                persist(e.message, inbox)
+            })
+        }
     }
     
     private boolean deliverTo(MWMessage message, Persona recipient) {
diff --git a/gui/griffon-app/models/com/muwire/gui/MainFrameModel.groovy b/gui/griffon-app/models/com/muwire/gui/MainFrameModel.groovy
index 5f2a4834..09d39012 100644
--- a/gui/griffon-app/models/com/muwire/gui/MainFrameModel.groovy
+++ b/gui/griffon-app/models/com/muwire/gui/MainFrameModel.groovy
@@ -857,12 +857,13 @@ class MainFrameModel {
     
     void onMessageReceivedEvent(MessageReceivedEvent e) {
         runInsideUIAsync {
-            messages++
-            messageHeadersMap.get(Messenger.INBOX).add(new MWMessageStatus(e.message, true))
-            if (folderIdx == Messenger.INBOX) {
-                messageHeaders.clear()
-                messageHeaders.addAll(messageHeadersMap.get(Messenger.INBOX))
-                view.messageHeaderTable.model.fireTableDataChanged()
+            if (messageHeadersMap.get(Messenger.INBOX).add(new MWMessageStatus(e.message, true))) {
+                messages++
+                if (folderIdx == Messenger.INBOX) {
+                    messageHeaders.clear()
+                    messageHeaders.addAll(messageHeadersMap.get(Messenger.INBOX))
+                    view.messageHeaderTable.model.fireTableDataChanged()
+                }
             }
         }
     }