diff --git a/mozilla/mailnews/base/src/nsMsgFolderCompactor.cpp b/mozilla/mailnews/base/src/nsMsgFolderCompactor.cpp
index 335ca5de053..9e4e43a6858 100644
--- a/mozilla/mailnews/base/src/nsMsgFolderCompactor.cpp
+++ b/mozilla/mailnews/base/src/nsMsgFolderCompactor.cpp
@@ -117,10 +117,10 @@ void nsFolderCompactState::CleanupTempFilesAfterError()
 
 nsresult nsFolderCompactState::BuildMessageURI(const char *baseURI, PRUint32 key, nsCString& uri)
 {
-	uri.Append(baseURI);
-	uri.Append('#');
-	uri.AppendInt(key);
-	return NS_OK;
+  uri.Append(baseURI);
+  uri.Append('#');
+  uri.AppendInt(key);
+  return NS_OK;
 }
 
 
@@ -411,26 +411,49 @@ nsFolderCompactState::FinishCompact()
   // close down database of the original folder and remove the folder node
   // and all it's message node from the tree
   m_folder->ForceDBClosed();
+
+  PRBool folderRenameSucceeded = PR_FALSE;
+  PRBool msfRenameSucceeded = PR_FALSE;
     // remove the old folder and database
   fileSpec.Delete(PR_FALSE);
-  summarySpec.Delete(PR_FALSE);
-    // rename the copied folder and database to be the original folder and
-    // database 
-  m_fileSpec.Rename(leafName.get());
-  newSummarySpec.Rename(dbName.get());
- 
+  if (!fileSpec.Exists())
+  {
+    summarySpec.Delete(PR_FALSE);
+    if (!summarySpec.Exists())
+    {
+      // rename the copied folder and database to be the original folder and
+      // database 
+      rv = m_fileSpec.Rename(leafName.get());
+      NS_ASSERTION(NS_SUCCEEDED(rv), "error renaming compacted folder");
+      if (NS_SUCCEEDED(rv))
+      {
+        folderRenameSucceeded = PR_TRUE;
+        rv = newSummarySpec.Rename(dbName.get());
+        NS_ASSERTION(NS_SUCCEEDED(rv), "error renaming compacted folder's db");
+        msfRenameSucceeded = NS_SUCCEEDED(rv);
+      }
+    }
+  }
+  NS_ASSERTION(msfRenameSucceeded && folderRenameSucceeded, "rename failed in compact");
+  if (!folderRenameSucceeded)
+    m_fileSpec.Delete(PR_FALSE);
+  if (!msfRenameSucceeded)
+    newSummarySpec.Delete(PR_FALSE);
   rv = ReleaseFolderLock();
   NS_ASSERTION(NS_SUCCEEDED(rv),"folder lock not released successfully");
-  m_folder->SetDBTransferInfo(transferInfo);
+  if (msfRenameSucceeded && folderRenameSucceeded)
+  {
+    m_folder->SetDBTransferInfo(transferInfo);
 
-  nsCOMPtr <nsIDBFolderInfo> dbFolderInfo;
+    nsCOMPtr <nsIDBFolderInfo> dbFolderInfo;
 
-  m_folder->GetDBFolderInfoAndDB(getter_AddRefs(dbFolderInfo), getter_AddRefs(m_db));
+    m_folder->GetDBFolderInfoAndDB(getter_AddRefs(dbFolderInfo), getter_AddRefs(m_db));
 
-  // since we're transferring info from the old db, we need to reset the expunged bytes,
-  // and set the summary valid again.
-  if(dbFolderInfo)
-    dbFolderInfo->SetExpungedBytes(0);
+    // since we're transferring info from the old db, we need to reset the expunged bytes,
+    // and set the summary valid again.
+    if(dbFolderInfo)
+      dbFolderInfo->SetExpungedBytes(0);
+  }
   if (m_db)
     m_db->Close(PR_TRUE);
   m_db = nsnull;
diff --git a/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp b/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
index 46f80ab15b6..70e9ca23e26 100644
--- a/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
+++ b/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
@@ -2747,7 +2747,7 @@ NS_IMETHODIMP nsMsgDatabase::ListAllKeys(nsMsgKeyArray &outputKeys)
   return err;
 }
 
-class nsMsgDBThreadEnumerator : public nsISimpleEnumerator
+class nsMsgDBThreadEnumerator : public nsISimpleEnumerator, public nsIDBChangeListener
 {
 public:
     NS_DECL_ISUPPORTS
@@ -2755,6 +2755,8 @@ public:
     // nsISimpleEnumerator methods:
     NS_DECL_NSISIMPLEENUMERATOR
 
+    NS_DECL_NSIDBCHANGELISTENER
+
     // nsMsgDBEnumerator methods:
     typedef nsresult (*nsMsgDBThreadEnumeratorFilter)(nsIMsgThread* thread);
 
@@ -2778,17 +2780,63 @@ nsMsgDBThreadEnumerator::nsMsgDBThreadEnumerator(nsMsgDatabase* db,
       mFilter(filter)
 {
     NS_ADDREF(mDB);
+    mDB->AddListener(this);
     mNextPrefetched = PR_FALSE;
 }
 
 nsMsgDBThreadEnumerator::~nsMsgDBThreadEnumerator()
 {
   mTableCursor->Release();
-	NS_IF_RELEASE(mResultThread);
-    NS_RELEASE(mDB);
+  NS_IF_RELEASE(mResultThread);
+  NS_IF_RELEASE(mDB);
 }
 
-NS_IMPL_ISUPPORTS1(nsMsgDBThreadEnumerator, nsISimpleEnumerator)
+NS_IMPL_ISUPPORTS2(nsMsgDBThreadEnumerator, nsISimpleEnumerator, nsIDBChangeListener)
+
+
+/* void onHdrChange (in nsIMsgDBHdr aHdrChanged, in unsigned long aOldFlags, in unsigned long aNewFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrChange(nsIMsgDBHdr *aHdrChanged, PRUint32 aOldFlags, PRUint32 aNewFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onHdrDeleted (in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrDeleted(nsIMsgDBHdr *aHdrChanged, nsMsgKey aParentKey, PRInt32 aFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onHdrAdded (in nsIMsgDBHdr aHdrChanged, in nsMsgKey aParentKey, in long aFlags, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnHdrAdded(nsIMsgDBHdr *aHdrChanged, nsMsgKey aParentKey, PRInt32 aFlags, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onParentChanged (in nsMsgKey aKeyChanged, in nsMsgKey oldParent, in nsMsgKey newParent, in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnParentChanged(nsMsgKey aKeyChanged, nsMsgKey oldParent, nsMsgKey newParent, nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onAnnouncerGoingAway (in nsIDBChangeAnnouncer instigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnAnnouncerGoingAway(nsIDBChangeAnnouncer *instigator)
+{
+  mDB->RemoveListener(this);
+  mDB = nsnull;
+  return NS_OK;
+}
+
+/* void onReadChanged (in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnReadChanged(nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
+
+/* void onJunkScoreChanged (in nsIDBChangeListener aInstigator); */
+NS_IMETHODIMP nsMsgDBThreadEnumerator::OnJunkScoreChanged(nsIDBChangeListener *aInstigator)
+{
+    return NS_OK;
+}
 
 nsresult nsMsgDBThreadEnumerator::GetTableCursor(void)
 {
@@ -2830,7 +2878,10 @@ nsresult nsMsgDBThreadEnumerator::PrefetchNext()
 {
   nsresult rv;
   nsIMdbTable *table = nsnull;
-  
+
+  if (!mDB)
+    return NS_ERROR_NULL_POINTER;
+
   if (!mTableCursor)
   {
     rv = GetTableCursor();