diff --git a/ws2012/P2P/uebungen/11/src/node/UDPHandler.java b/ws2012/P2P/uebungen/11/src/node/UDPHandler.java
index 537d6e00..ef592fa7 100644
--- a/ws2012/P2P/uebungen/11/src/node/UDPHandler.java
+++ b/ws2012/P2P/uebungen/11/src/node/UDPHandler.java
@@ -246,7 +246,10 @@ public class UDPHandler implements Runnable {
                 if(chunklist.get(fid) == null){
                     chunklist.put(fid, new HashMap<Integer,String>());
                 }
-                chunklist.get(fid).put(chunkID, chunkContent);
+                
+                if(chunklist.get(fid).get(chunkID) == null){
+                	chunklist.get(fid).put(chunkID, chunkContent);
+                }
 
                 if(chunklist.get(fid).size() >= chunkCount){
                     LOGGER.log(Level.INFO,"FILE complete file: "+fileID+" count: "+chunkCount+" id: "+chunkID);