diff --git a/src/session.cpp b/src/session.cpp
index 2d383d1dd..7729e2166 100644
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -262,21 +262,21 @@ namespace libtorrent
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_wrap, &done, &m_impl->cond, &m_impl->mut, boost::function<void(void)>(boost::bind(&session_impl:: x, m_impl.get())))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL1(x, a1) \
 	bool done = false; \
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_wrap, &done, &m_impl->cond, &m_impl->mut, boost::function<void(void)>(boost::bind(&session_impl:: x, m_impl.get(), a1)))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL2(x, a1, a2) \
 	bool done = false; \
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_wrap, &done, &m_impl->cond, &m_impl->mut, boost::function<void(void)>(boost::bind(&session_impl:: x, m_impl.get(), a1, a2)))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL_RET(type, x) \
 	bool done = false; \
@@ -284,7 +284,7 @@ namespace libtorrent
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_ret<type>, &r, &done, &m_impl->cond, &m_impl->mut, boost::function<type(void)>(boost::bind(&session_impl:: x, m_impl.get())))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL_RET1(type, x, a1) \
 	bool done = false; \
@@ -292,7 +292,7 @@ namespace libtorrent
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_ret<type>, &r, &done, &m_impl->cond, &m_impl->mut, boost::function<type(void)>(boost::bind(&session_impl:: x, m_impl.get(), a1)))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL_RET2(type, x, a1, a2) \
 	bool done = false; \
@@ -300,7 +300,7 @@ namespace libtorrent
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_ret<type>, &r, &done, &m_impl->cond, &m_impl->mut, boost::function<type(void)>(boost::bind(&session_impl:: x, m_impl.get(), a1, a2)))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 #define TORRENT_SYNC_CALL_RET3(type, x, a1, a2, a3) \
 	bool done = false; \
@@ -308,7 +308,7 @@ namespace libtorrent
 	mutex::scoped_lock l(m_impl->mut); \
 	m_impl->cond.clear(l); \
 	m_impl->m_io_service.post(boost::bind(&fun_ret<type>, &r, &done, &m_impl->cond, &m_impl->mut, boost::function<type(void)>(boost::bind(&session_impl:: x, m_impl.get(), a1, a2, a3)))); \
-	do { m_impl->cond.wait(l); } while(!done)
+	do { m_impl->cond.wait(l); m_impl->cond.clear(l); } while(!done)
 
 	session::session(
 		fingerprint const& id