diff --git a/src/main.cpp b/src/main.cpp
index 6ffbc5a4..56bd7a5c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2355,7 +2355,7 @@ bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW, bo
         uniqueTx.insert(block.GetTxHash(i));
     }
     if (uniqueTx.size() != block.vtx.size())
-        return state.DoS(100, error("CheckBlock() : duplicate transaction"));
+        return state.DoS(100, error("CheckBlock() : duplicate transaction"), true);
 
     unsigned int nSigOps = 0;
     BOOST_FOREACH(const CTransaction& tx, block.vtx)
@@ -3783,7 +3783,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
         LOCK(cs_main);
 
         CValidationState state;
-        if (ProcessBlock(state, pfrom, &block))
+        if (ProcessBlock(state, pfrom, &block) || state.CorruptionPossible())
             mapAlreadyAskedFor.erase(inv);
         int nDoS = 0;
         if (state.IsInvalid(nDoS))
diff --git a/src/main.h b/src/main.h
index 76de4707..2a67747b 100644
--- a/src/main.h
+++ b/src/main.h
@@ -946,13 +946,15 @@ private:
         MODE_ERROR,   // run-time error
     } mode;
     int nDoS;
+    bool corruptionPossible;
 public:
     CValidationState() : mode(MODE_VALID), nDoS(0) {}
-    bool DoS(int level, bool ret = false) {
+    bool DoS(int level, bool ret = false, bool corruptionIn = false) {
         if (mode == MODE_ERROR)
             return ret;
         nDoS += level;
         mode = MODE_INVALID;
+        corruptionPossible = corruptionIn;
         return ret;
     }
     bool Invalid(bool ret = false) {
@@ -982,6 +984,9 @@ public:
         }
         return false;
     }
+    bool CorruptionPossible() {
+        return corruptionPossible;
+    }
 };
 
 /** An in-memory indexed chain of blocks. */