diff --git a/hbs2-peer/app/CLI/Mailbox.hs b/hbs2-peer/app/CLI/Mailbox.hs
index 775092bc..0c150387 100644
--- a/hbs2-peer/app/CLI/Mailbox.hs
+++ b/hbs2-peer/app/CLI/Mailbox.hs
@@ -253,7 +253,7 @@ runMailboxCLI rpc s = do
                       Deleted _ mh -> do
                         atomically $ modifyTVar d (HS.insert mh)
 
-                      Existed _ mh -> do
+                      Exists _ mh -> do
                          atomically $ modifyTVar r (HS.insert mh)
 
               deleted <- readTVarIO d
diff --git a/hbs2-peer/app/MailboxProtoWorker.hs b/hbs2-peer/app/MailboxProtoWorker.hs
index 35411d26..9d03bbea 100644
--- a/hbs2-peer/app/MailboxProtoWorker.hs
+++ b/hbs2-peer/app/MailboxProtoWorker.hs
@@ -508,7 +508,7 @@ mailboxProtoWorker readConf me@MailboxProtoWorker{..} = do
 
             -- TODO: add-policy-reference
             let proof = ProofOfExist mzero
-            h' <- enqueueBlock sto (serialise (Existed proof ha))
+            h' <- enqueueBlock sto (serialise (Exists proof ha))
 
             for_ h' $ \h -> do
               atomically do
@@ -558,6 +558,11 @@ mailboxProtoWorker readConf me@MailboxProtoWorker{..} = do
         updateRef sto r nref
         debug $ yellow "mailbox updated" <+> pretty r <+> pretty nref
 
+        for_ newTx $ \t -> do
+          -- FIXME: use-bloom-filter-or-something
+          --  $class: leak
+          putBlock sto (serialise (MergedEntry r t))
+
     policyDownloadQ dbe = do
 
       -- FIXME: too-often-checks-affect-performance
@@ -602,22 +607,89 @@ mailboxProtoWorker readConf me@MailboxProtoWorker{..} = do
       polling (Polling 30 30) mail $ \(pk, down@MailboxDownload{..}) -> do
         done <- findMissedBlocks mpwStorage mailboxStatusRef <&> L.null
 
+        fails <- newTVarIO 0
+
         when (done && not mailboxDownDone) do
           atomically $ modifyTVar inMailboxDownloadQ (HM.insert pk (down { mailboxDownDone = True }))
           debug $ "mailbox state downloaded" <+> pretty pk
 
         when done do
           debug $ "mailbox/debug: drop state" <+> pretty pk <+> pretty mailboxStatusRef
-          atomically $ modifyTVar inMailboxDownloadQ (HM.delete pk)
 
           -- FIXME: assume-huge-mailboxes
 
           walkMerkle @[HashRef] (coerce mailboxStatusRef) (getBlock mpwStorage) $ \case
-            Left what -> err $ red "mailbox: missed block for tree" <+> pretty mailboxStatusRef
-            Right hs  -> void $ runMaybeT do
-              for_ hs $ \h -> do
+            Left what -> do
+              err $ red "mailbox: missed block for tree" <+> pretty mailboxStatusRef <+> pretty what
+              atomically $ modifyTVar fails succ
+
+            Right hs  ->  do
+              for_ hs $ \h -> void $ runMaybeT do
                 debug $ red ">>>" <+> "MERGE MAILBOX ENTRY" <+> pretty h
 
+                -- FIXME: invent-better-filter
+                --  $class: leak
+                let mergedEntry = serialise (MergedEntry mailboxRef h)
+                let mergedH = mergedEntry & hashObject
+
+                already <- getBlock mpwStorage mergedH
+
+                when (isJust already) do
+                  debug $ red "!!!" <+> "skip already merged tx" <+> pretty h
+                  mzero
+
+                entry' <- getBlock mpwStorage (coerce h)
+
+                when (isNothing entry') do
+                  startDownloadStuff me h
+                  atomically $ modifyTVar fails succ
+                  mzero
+
+                entry <- toMPlus entry'
+                           <&> deserialiseOrFail @MailboxEntry
+                           >>= toMPlus
+
+                case entry of
+                  Deleted{} -> do
+                    atomically $ modifyTVar inMessageMergeQueue (HM.insert mailboxRef (HS.singleton h))
+                    -- write-already-merged
+
+                  Exists _ w -> do
+                    msg' <- getBlock mpwStorage (coerce w)
+
+                    case msg' of
+                      Nothing -> do
+                        startDownloadStuff me h
+                        atomically $ modifyTVar fails succ
+                        mzero
+
+                      Just msg -> do
+                        let mess = deserialiseOrFail @(Message s) msg
+
+                        case mess of
+                          Left{} -> do
+                            warn $ "malformed message" <+> pretty w
+                            void $ putBlock mpwStorage mergedEntry
+
+                          Right normal -> do
+                            let checked = unboxSignedBox0 (messageContent normal)
+
+                            case checked of
+                              Nothing -> do
+                                warn $ "invalid signature for message" <+> pretty w
+                                void $ putBlock mpwStorage mergedEntry
+
+                              Just (_, content) -> do
+                                -- FIXME: what-if-message-queue-full?
+                                mailboxAcceptMessage me normal content
+                                pure ()
+
+          failNum <- readTVarIO fails
+
+          when (failNum == 0) do
+            debug $ "mailbox state process succeed" <+> pretty mailboxStatusRef
+            atomically $ modifyTVar inMailboxDownloadQ (HM.delete pk)
+
     mailboxFetchQ dbe = forever do
       toFetch <- atomically $ do
         q <- readTVar mpwFetchQ
diff --git a/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox.hs b/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox.hs
index 95575ba7..62b69e97 100644
--- a/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox.hs
+++ b/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox.hs
@@ -33,6 +33,12 @@ import Data.Maybe
 import Data.Word
 import Lens.Micro.Platform
 
+
+data MergedEntry s = MergedEntry (MailboxRefKey s) HashRef
+                   deriving stock (Generic)
+
+instance ForMailbox s => Serialise (MergedEntry s)
+
 data SetPolicyPayload s =
   SetPolicyPayload
   { sppMailboxKey    :: MailboxKey s
diff --git a/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox/Entry.hs b/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox/Entry.hs
index 15149126..2036a4f5 100644
--- a/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox/Entry.hs
+++ b/hbs2-peer/lib/HBS2/Peer/Proto/Mailbox/Entry.hs
@@ -33,18 +33,19 @@ instance Semigroup ProofOfExist where
   (<>) (ProofOfExist a1) (ProofOfExist a2) = ProofOfExist (a1 <|> a2)
 
 data MailboxEntry =
-    Existed ProofOfExist  HashRef
+    Exists ProofOfExist  HashRef
   | Deleted ProofOfDelete HashRef  -- ^ proof-of-message-to-validate
   deriving stock (Eq,Ord,Show,Generic)
 
 instance Hashable MailboxEntry where
   hashWithSalt salt = \case
-    Existed p r -> hashWithSalt salt (0x177c1a3ad45b678e :: Word64, serialise (p,r))
+    Exists p r -> hashWithSalt salt (0x177c1a3ad45b678e :: Word64, serialise (p,r))
     Deleted p r -> hashWithSalt salt (0xac3196b4809ea027 :: Word64, serialise (p,r))
 
 data RoutedEntry = RoutedEntry HashRef
                    deriving stock (Eq,Ord,Show,Generic)
 
+
 instance Serialise MailboxEntry
 instance Serialise RoutedEntry
 instance Serialise ProofOfDelete