diff --git a/ethchain/state.go b/ethchain/state.go
index db715f1cb1..6ec6916f46 100644
--- a/ethchain/state.go
+++ b/ethchain/state.go
@@ -60,6 +60,7 @@ func (s *State) GetStateObject(addr []byte) *StateObject {
 	// Check if there's a cached state for this contract
 	cachedStateObject := s.states[string(addr)]
 	if cachedStateObject != nil {
+		//fmt.Printf("get cached #%d %x addr: %x\n", cachedStateObject.trie.Cache().Len(), cachedStateObject.Root(), addr[0:4])
 		stateObject.state = cachedStateObject
 	}
 
@@ -70,8 +71,9 @@ func (s *State) GetStateObject(addr []byte) *StateObject {
 func (s *State) UpdateStateObject(object *StateObject) {
 	addr := object.Address()
 
-	if object.state != nil {
+	if object.state != nil && s.states[string(addr)] == nil {
 		s.states[string(addr)] = object.state
+		//fmt.Printf("update cached #%d %x addr: %x\n", object.state.trie.Cache().Len(), object.state.Root(), addr[0:4])
 	}
 
 	ethutil.Config.Db.Put(ethutil.Sha3Bin(object.Script()), object.Script())
@@ -81,12 +83,6 @@ func (s *State) UpdateStateObject(object *StateObject) {
 	s.manifest.AddObjectChange(object)
 }
 
-func (s *State) SetStateObject(stateObject *StateObject) {
-	s.states[string(stateObject.address)] = stateObject.state
-
-	s.UpdateStateObject(stateObject)
-}
-
 func (s *State) GetAccount(addr []byte) (account *StateObject) {
 	data := s.trie.Get(string(addr))
 	if data == "" {
diff --git a/ethchain/state_object.go b/ethchain/state_object.go
index cb6211ea61..8e059f3344 100644
--- a/ethchain/state_object.go
+++ b/ethchain/state_object.go
@@ -78,6 +78,7 @@ func (c *StateObject) SetAddr(addr []byte, value interface{}) {
 
 func (c *StateObject) SetStorage(num *big.Int, val *ethutil.Value) {
 	addr := ethutil.BigToBytes(num, 256)
+	//fmt.Println("storing", val.BigInt(), "@", num)
 	c.SetAddr(addr, val)
 }
 
diff --git a/ethchain/vm.go b/ethchain/vm.go
index e732d22a42..c4304e5ac1 100644
--- a/ethchain/vm.go
+++ b/ethchain/vm.go
@@ -448,7 +448,7 @@ func (vm *Vm) RunClosure(closure *Closure, hook DebugHook) (ret []byte, err erro
 			} else {
 				stack.Push(ethutil.BigD(addr))
 
-				vm.state.SetStateObject(contract)
+				vm.state.UpdateStateObject(contract)
 			}
 		case oCALL:
 			require(7)
@@ -497,7 +497,7 @@ func (vm *Vm) RunClosure(closure *Closure, hook DebugHook) (ret []byte, err erro
 					stack.Push(ethutil.BigTrue)
 				}
 
-				vm.state.SetStateObject(contract)
+				vm.state.UpdateStateObject(contract)
 
 				mem.Set(retOffset.Int64(), retSize.Int64(), ret)
 			} else {
@@ -515,7 +515,7 @@ func (vm *Vm) RunClosure(closure *Closure, hook DebugHook) (ret []byte, err erro
 
 			receiver := vm.state.GetAccount(stack.Pop().Bytes())
 			receiver.AddAmount(closure.object.Amount)
-			vm.state.SetStateObject(receiver)
+			vm.state.UpdateStateObject(receiver)
 
 			closure.object.state.Purge()
 
diff --git a/ethpub/pub.go b/ethpub/pub.go
index fb1018d471..ec187e276a 100644
--- a/ethpub/pub.go
+++ b/ethpub/pub.go
@@ -162,7 +162,7 @@ func (lib *PEthereum) createTx(key, recipient, valueStr, gasStr, gasPriceStr, in
 	acc := lib.stateManager.TransState().GetStateObject(keyPair.Address())
 	tx.Nonce = acc.Nonce
 	acc.Nonce += 1
-	lib.stateManager.TransState().SetStateObject(acc)
+	lib.stateManager.TransState().UpdateStateObject(acc)
 
 	tx.Sign(keyPair.PrivateKey)
 	lib.txPool.QueueTransaction(tx)
diff --git a/ethutil/trie.go b/ethutil/trie.go
index 4d088ccff2..c993e4d8f3 100644
--- a/ethutil/trie.go
+++ b/ethutil/trie.go
@@ -3,8 +3,13 @@ package ethutil
 import (
 	"fmt"
 	"reflect"
+	"sync"
 )
 
+func (s *Cache) Len() int {
+	return len(s.nodes)
+}
+
 // TODO
 // A StateObject is an object that has a state root
 // This is goig to be the object for the second level caching (the caching of object which have a state such as contracts)
@@ -113,6 +118,7 @@ func (cache *Cache) Undo() {
 // Please note that the data isn't persisted unless `Sync` is
 // explicitly called.
 type Trie struct {
+	mut      sync.RWMutex
 	prevRoot interface{}
 	Root     interface{}
 	//db   Database
@@ -157,12 +163,18 @@ func (t *Trie) Cache() *Cache {
  * Public (query) interface functions
  */
 func (t *Trie) Update(key string, value string) {
+	t.mut.Lock()
+	defer t.mut.Unlock()
+
 	k := CompactHexDecode(key)
 
 	t.Root = t.UpdateState(t.Root, k, value)
 }
 
 func (t *Trie) Get(key string) string {
+	t.mut.RLock()
+	defer t.mut.RUnlock()
+
 	k := CompactHexDecode(key)
 	c := NewValue(t.GetState(t.Root, k))