diff --git a/node/handler/PadMessageHandler.js b/node/handler/PadMessageHandler.js
index f89f4934..438f0ff3 100644
--- a/node/handler/PadMessageHandler.js
+++ b/node/handler/PadMessageHandler.js
@@ -809,10 +809,15 @@ function handleClientReady(client, message)
       //Send the clientVars to the Client
       client.json.send(clientVars);
       
-      //Save the revision and the author id in sessioninfos
-      sessioninfos[client.id].rev = pad.getHeadRevisionNumber();
-      sessioninfos[client.id].author = author;
-      
+      //sometimes the client disconnects very early and the session of it is already removed
+      //thats why we have to check that case
+      if(sessioninfos[client.id] !== undefined)
+      {
+        //Save the revision and the author id in sessioninfos
+        sessioninfos[client.id].rev = pad.getHeadRevisionNumber();
+        sessioninfos[client.id].author = author;
+      }
+
       //prepare the notification for the other users on the pad, that this user joined
       var messageToTheOtherUsers = {
         "type": "COLLABROOM",