diff --git a/lib/synchronizer.py b/lib/synchronizer.py
index 4b81810db..f3f4cbb5f 100644
--- a/lib/synchronizer.py
+++ b/lib/synchronizer.py
@@ -50,6 +50,8 @@ class Synchronizer(ThreadJob):
         self.requested_histories = {}
         self.requested_addrs = set()
         self.lock = Lock()
+
+        self.initialized = False
         self.initialize()
 
     def parse_response(self, response):
@@ -84,7 +86,7 @@ class Synchronizer(ThreadJob):
         return bh2u(hashlib.sha256(status.encode('ascii')).digest())
 
     def on_address_status(self, response):
-        if self.wallet.synchronizer is None:
+        if self.wallet.synchronizer is None and self.initialized:
             return  # we have been killed, this was just an orphan callback
         params, result = self.parse_response(response)
         if not params:
@@ -100,7 +102,7 @@ class Synchronizer(ThreadJob):
             self.requested_addrs.remove(addr)
 
     def on_address_history(self, response):
-        if self.wallet.synchronizer is None:
+        if self.wallet.synchronizer is None and self.initialized:
             return  # we have been killed, this was just an orphan callback
         params, result = self.parse_response(response)
         if not params:
@@ -131,7 +133,7 @@ class Synchronizer(ThreadJob):
         self.requested_histories.pop(addr)
 
     def tx_response(self, response):
-        if self.wallet.synchronizer is None:
+        if self.wallet.synchronizer is None and self.initialized:
             return  # we have been killed, this was just an orphan callback
         params, result = self.parse_response(response)
         if not params:
@@ -183,6 +185,7 @@ class Synchronizer(ThreadJob):
         if self.requested_tx:
             self.print_error("missing tx", self.requested_tx)
         self.subscribe_to_addresses(set(self.wallet.get_addresses()))
+        self.initialized = True
 
     def run(self):
         '''Called from the network proxy thread main loop.'''