diff --git a/mozilla/mailnews/imap/src/nsImapUndoTxn.cpp b/mozilla/mailnews/imap/src/nsImapUndoTxn.cpp
index 642b71dc203..a50a117c014 100644
--- a/mozilla/mailnews/imap/src/nsImapUndoTxn.cpp
+++ b/mozilla/mailnews/imap/src/nsImapUndoTxn.cpp
@@ -189,6 +189,12 @@ nsImapMoveCopyMsgTxn::UndoTransaction(void)
       nsMsgImapDeleteModel deleteModel;
       rv = GetImapDeleteModel(srcFolder, &deleteModel);
 
+      // protect against a bogus undo txn without any source keys
+      // see bug #179856 for details
+      NS_ASSERTION(m_srcKeyArray.GetSize(), "no source keys");
+      if (!m_srcKeyArray.GetSize())
+        return NS_ERROR_UNEXPECTED;
+
       if (NS_SUCCEEDED(rv) && deleteModel == nsMsgImapDeleteModels::IMAPDelete)
         CheckForToggleDelete(srcFolder, m_srcKeyArray.GetAt(0), &deletedMsgs);
 
@@ -263,6 +269,13 @@ nsImapMoveCopyMsgTxn::RedoTransaction(void)
             PRBool deletedMsgs = PR_FALSE;  //default will be false unless imapDeleteModel;
             nsMsgImapDeleteModel deleteModel;
             rv = GetImapDeleteModel(srcFolder, &deleteModel);
+            
+            // protect against a bogus undo txn without any source keys
+            // see bug #179856 for details
+            NS_ASSERTION(m_srcKeyArray.GetSize(), "no source keys");
+            if (!m_srcKeyArray.GetSize())
+              return NS_ERROR_UNEXPECTED;
+
             if (NS_SUCCEEDED(rv) && deleteModel == nsMsgImapDeleteModels::IMAPDelete)
               rv = CheckForToggleDelete(srcFolder, m_srcKeyArray.GetAt(0), &deletedMsgs);
 
diff --git a/mozilla/mailnews/local/src/nsLocalMailFolder.cpp b/mozilla/mailnews/local/src/nsLocalMailFolder.cpp
index 1f7928d259e..5899b612eda 100644
--- a/mozilla/mailnews/local/src/nsLocalMailFolder.cpp
+++ b/mozilla/mailnews/local/src/nsLocalMailFolder.cpp
@@ -2539,11 +2539,11 @@ NS_IMETHODIMP nsMsgLocalMailFolder::EndCopy(PRBool copySucceeded)
       NS_ENSURE_SUCCESS(rv,rv);
     }
   }
-	//Copy the header to the new database
-	if(copySucceeded && mCopyState->m_message)
-	{ //  CopyMessages() goes here; CopyFileMessage() never gets in here because
+  //Copy the header to the new database
+  if(copySucceeded && mCopyState->m_message)
+  { //  CopyMessages() goes here; CopyFileMessage() never gets in here because
     //  the mCopyState->m_message will be always null for file message
-
+    
     nsCOMPtr<nsIMsgDBHdr> newHdr;
     
     if(!mCopyState->m_parseMsgState)
@@ -2551,36 +2551,38 @@ NS_IMETHODIMP nsMsgLocalMailFolder::EndCopy(PRBool copySucceeded)
       if(mDatabase)
       {
         rv = mDatabase->CopyHdrFromExistingHdr(mCopyState->m_curDstKey,
-                                               mCopyState->m_message, PR_TRUE,
-                                               getter_AddRefs(newHdr));
+          mCopyState->m_message, PR_TRUE,
+          getter_AddRefs(newHdr));
         PRUint32 newHdrFlags;
-
-
         // turn off offline flag - it's not valid for local mail folders.
         if (newHdr)
           newHdr->AndFlags(~MSG_FLAG_OFFLINE, &newHdrFlags);
-
-        PRBool isImap;
-        if (NS_SUCCEEDED(rv) && localUndoTxn)
-          localUndoTxn->GetSrcIsImap(&isImap);
-        if (NS_SUCCEEDED(rv) && localUndoTxn && (!isImap || !mCopyState->m_copyingMultipleMessages))
-        {
-          nsMsgKey aKey;
-          mCopyState->m_message->GetMessageKey(&aKey);
-          localUndoTxn->AddSrcKey(aKey);
-          localUndoTxn->AddDstKey(mCopyState->m_curDstKey);
-        }
       }
       else
         mCopyState->m_undoMsgTxn = nsnull; //null out the transaction because we can't undo w/o the msg db
     }
+    
+    // if we plan on allowing undo, (if we have a mCopyState->m_parseMsgState or not)
+    // we need to save the source and dest keys on the undo txn.
+    // see bug #179856 for details
+    PRBool isImap;
+    if (NS_SUCCEEDED(rv) && localUndoTxn) {
+      localUndoTxn->GetSrcIsImap(&isImap);
+      if (!isImap || !mCopyState->m_copyingMultipleMessages)
+      {
+        nsMsgKey aKey;
+        mCopyState->m_message->GetMessageKey(&aKey);
+        localUndoTxn->AddSrcKey(aKey);
+        localUndoTxn->AddDstKey(mCopyState->m_curDstKey);
+      }
+    }
   }
   if (mCopyState->m_dummyEnvelopeNeeded)
   {
     mCopyState->m_fileStream->seek(PR_SEEK_END, 0);
     *(mCopyState->m_fileStream) << MSG_LINEBREAK;
     if (mCopyState->m_parseMsgState)
-        mCopyState->m_parseMsgState->ParseAFolderLine(CRLF, MSG_LINEBREAK_LEN);
+      mCopyState->m_parseMsgState->ParseAFolderLine(CRLF, MSG_LINEBREAK_LEN);
   }
 
   // CopyFileMessage() and CopyMessages() from servers other than mailbox
diff --git a/mozilla/mailnews/local/src/nsLocalUndoTxn.cpp b/mozilla/mailnews/local/src/nsLocalUndoTxn.cpp
index 313ecb73100..786526b61aa 100644
--- a/mozilla/mailnews/local/src/nsLocalUndoTxn.cpp
+++ b/mozilla/mailnews/local/src/nsLocalUndoTxn.cpp
@@ -244,6 +244,12 @@ nsLocalMoveCopyMsgTxn::UndoTransaction()
     nsCOMPtr<nsIMsgDBHdr> oldHdr;
     nsCOMPtr<nsIMsgDBHdr> newHdr;
 
+    // protect against a bogus undo txn without any source keys
+    // see bug #179856 for details
+    NS_ASSERTION(count, "no source keys");
+    if (!count)
+      return NS_ERROR_UNEXPECTED;
+
     if (m_isMove)
     {
         if (m_srcIsImap4)
@@ -349,6 +355,12 @@ nsLocalMoveCopyMsgTxn::RedoTransaction()
     {
         if (m_srcIsImap4)
         {
+            // protect against a bogus undo txn without any source keys
+            // see bug #179856 for details
+            NS_ASSERTION(m_srcKeyArray.GetSize(), "no source keys");
+            if (!m_srcKeyArray.GetSize())
+              return NS_ERROR_UNEXPECTED;
+          
             PRBool deleteFlag = PR_FALSE; //message is un-deleted- we are trying to redo
             CheckForToggleDelete(srcFolder, m_srcKeyArray.GetAt(0), &deleteFlag); // there could have been a toggle
             rv = UndoImapDeleteFlag(srcFolder, m_srcKeyArray, deleteFlag);