diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## 0.16.4
+### Removed
+- Remove concurrency from requests using iterators to prevent RocksDB from segfaulting.
+
 ## 0.16.3
 ### Added
 - Debugging information for web API.
diff --git a/haskoin-store.cabal b/haskoin-store.cabal
--- a/haskoin-store.cabal
+++ b/haskoin-store.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 8d7ecfe8340a37feb3963de53242a033672aa794f96a5133090643117a1b8de9
+-- hash: 8ab386452576005ff6acda2b569d7e1219303832c0c0271c8a43b4c32e960acc
 
 name:           haskoin-store
-version:        0.16.3
+version:        0.16.4
 synopsis:       Storage and index for Bitcoin and Bitcoin Cash
 description:    Store blocks, transactions, and balances for Bitcoin or Bitcoin Cash, and make that information via REST API.
 category:       Bitcoin, Finance, Network
diff --git a/src/Network/Haskoin/Store/Web.hs b/src/Network/Haskoin/Store/Web.hs
--- a/src/Network/Haskoin/Store/Web.hs
+++ b/src/Network/Haskoin/Store/Web.hs
@@ -885,23 +885,14 @@
     -> XPubKey
     -> ConduitT () XPubUnspent m ()
 xpubUnspent net mbr xpub = do
-    (_, as) <-
-        lift $ allocate (newTVarIO []) (readTVarIO >=> mapM_ cancel)
-    xs <-
-        lift $ do
-            bals <- xpubBals xpub
-            forM bals $ \XPubBal {xPubBalPath = p, xPubBal = b} ->
-                mask_ $ do
-                    q <- newTBQueueIO 10
-                    a <-
-                        async . runConduit $
-                        getAddressUnspents (balanceAddress b) mbr .| mapC (f p) .|
-                        conduitToQueue q
-                    atomically $ modifyTVar as (a :)
-                    return $ queueToConduit q
+    xs <- do
+        bs <- lift $ xpubBals xpub
+        return $ map g bs
     mergeSourcesBy (flip compare `on` (unspentBlock . xPubUnspent)) xs
   where
     f p t = XPubUnspent {xPubUnspentPath = p, xPubUnspent = t}
+    g XPubBal {xPubBalPath = p, xPubBal = b} =
+        getAddressUnspents (balanceAddress b) mbr .| mapC (f p)
 
 xpubUnspentLimit ::
        ( MonadResource m
@@ -1062,19 +1053,11 @@
     -> StartFrom
     -> [Address]
     -> ConduitT () BlockTx m ()
-getAddressesTxsLimit l s addrs = do
-    (_, ss) <- lift $ allocate (newTVarIO []) (readTVarIO >=> mapM_ cancel)
-    xs <-
-        lift . forM addrs $ \addr ->
-            mask_ $ do
-                q <- newTBQueueIO 10
-                a <-
-                    async . runConduit $
-                    getAddressTxs addr (mbr s) .| conduitToQueue q
-                atomically $ modifyTVar ss (a :)
-                return $ queueToConduit q
+getAddressesTxsLimit l s as =
     mergeSourcesBy (flip compare `on` blockTxBlock) xs .| dedup .|
-        (offset s >> limit l)
+    (offset s >> limit l)
+  where
+    xs = map (\a -> getAddressTxs a (mbr s)) as
 
 getAddressesTxsFull ::
        (MonadResource m, MonadUnliftIO m, StoreStream m, StoreRead m)