diff --git a/mozilla/mailnews/base/src/nsMsgFolderCache.cpp b/mozilla/mailnews/base/src/nsMsgFolderCache.cpp
index 49f64536329..9d080c7d799 100644
--- a/mozilla/mailnews/base/src/nsMsgFolderCache.cpp
+++ b/mozilla/mailnews/base/src/nsMsgFolderCache.cpp
@@ -31,7 +31,6 @@
 
 #include "nsXPIDLString.h"
 #include "nsMsgBaseCID.h"
-#include "nsIArena.h"
 
 static NS_DEFINE_CID(kMorkCID, NS_MORK_CID);
 static NS_DEFINE_CID(kCMsgMailSessionCID, NS_MSGMAILSESSION_CID); 
@@ -39,26 +38,6 @@ static NS_DEFINE_CID(kCMsgMailSessionCID, NS_MSGMAILSESSION_CID);
 const char *kFoldersScope = "ns:msg:db:row:scope:folders:all";	// scope for all folders table
 const char *kFoldersTableKind = "ns:msg:db:table:kind:folders";
 
-class FolderCachePool : public nsIMdbHeap { // caller-supplied memory management interface
-public:
-// { ===== begin nsIMdbHeap methods =====
-  virtual mdb_err Alloc(nsIMdbEnv* ev, // allocate a piece of memory
-    mdb_size inSize,        // requested byte size of new memory block 
-    void** outBlock);   // memory block of inSize bytes, or nil
-    
-  virtual mdb_err Free(nsIMdbEnv* ev, // free block from Alloc or Resize()
-    void* ioBlock);     // block to be destroyed/deallocated
-    
-  virtual mdb_err HeapAddStrongRef(nsIMdbEnv* ev);
-  virtual mdb_err HeapCutStrongRef(nsIMdbEnv* ev);
-    
-// } ===== end nsIMdbHeap methods =====
-  nsresult Init();
-  virtual ~FolderCachePool() {};
-protected:
-	nsCOMPtr <nsIArena> m_arena;
-};
-
 
 nsMsgFolderCache::nsMsgFolderCache()
 {
@@ -66,9 +45,6 @@ nsMsgFolderCache::nsMsgFolderCache()
 	m_mdbStore = nsnull;
 	NS_INIT_REFCNT();
 	m_mdbAllFoldersTable = nsnull;
-	m_morkEnvMemPool = new FolderCachePool;
-	if (m_morkEnvMemPool)
-		m_morkEnvMemPool->Init();
 }
 
 // should this, could this be an nsCOMPtr ?
@@ -90,7 +66,6 @@ nsMsgFolderCache::~nsMsgFolderCache()
 		m_mdbEnv->CloseMdbObject(m_mdbEnv);
 //		m_mdbEnv->CutStrongRef(m_mdbEnv); //??? is this right?
 	}
-	delete m_morkEnvMemPool;
 }
 
 
@@ -215,42 +190,13 @@ nsresult nsMsgFolderCache::InitExistingDB()
 	return err;
 }
 
-mdb_err FolderCachePool::Alloc(nsIMdbEnv* ev, // allocate a piece of memory
-    mdb_size inSize,        // requested byte size of new memory block 
-    void** outBlock)
-{
-	*outBlock = m_arena->Alloc(inSize);
-	return (*outBlock) ? 0 : (mdb_err) -1;
-}
-
-mdb_err FolderCachePool::Free(nsIMdbEnv* ev, // free block from Alloc or Resize()
-    void* ioBlock)     // block to be destroyed/deallocated
-{
-	return 0;
-}
-    
-mdb_err FolderCachePool::HeapAddStrongRef(nsIMdbEnv* ev)
-{
-	return 0;
-}
-
-mdb_err FolderCachePool::HeapCutStrongRef(nsIMdbEnv* ev)
-{
-	return 0;
-}
-
-nsresult FolderCachePool::Init()
-{
-	return NS_NewHeapArena(getter_AddRefs(m_arena), 1024);
-}
-
 nsresult nsMsgFolderCache::OpenMDB(const char *dbName, PRBool exists)
 {
 	nsresult ret=NS_OK;
 	nsIMdbFactory *myMDBFactory = GetMDBFactory();
 	if (myMDBFactory)
 	{
-		ret = myMDBFactory->MakeEnv(m_morkEnvMemPool, &m_mdbEnv);
+		ret = myMDBFactory->MakeEnv(nsnull, &m_mdbEnv);
 		if (NS_SUCCEEDED(ret))
 		{
 			nsIMdbThumb *thumb = nsnull;
diff --git a/mozilla/mailnews/base/src/nsMsgFolderCache.h b/mozilla/mailnews/base/src/nsMsgFolderCache.h
index 5b62502477d..f180fc7dea1 100644
--- a/mozilla/mailnews/base/src/nsMsgFolderCache.h
+++ b/mozilla/mailnews/base/src/nsMsgFolderCache.h
@@ -30,8 +30,6 @@
 #include "mdb.h"
 #include "nsHashtable.h"
 
-class FolderCachePool;
-
 class nsMsgFolderCache : public nsIMsgFolderCache
 {
 
@@ -59,7 +57,6 @@ protected:
 
 	nsFileSpec		m_dbFileSpec;
 	nsSupportsHashtable	*m_cacheElements;
-	FolderCachePool		*m_morkEnvMemPool;
 	// mdb stuff
 	nsIMdbEnv		    *m_mdbEnv;	// to be used in all the db calls.
 	nsIMdbStore	 	    *m_mdbStore;