diff --git a/src/jrd/EngineInterface.h b/src/jrd/EngineInterface.h
index 02e39b39a4..24ea89bf2c 100644
--- a/src/jrd/EngineInterface.h
+++ b/src/jrd/EngineInterface.h
@@ -385,7 +385,6 @@ public:
 
 public:
 	explicit JService(Jrd::Service* handle);
-	Firebird::Mutex mutex;
 	Jrd::Service* svc;
 
 private:
diff --git a/src/jrd/jrd.cpp b/src/jrd/jrd.cpp
index c1bfbdb1c3..decf11ce11 100644
--- a/src/jrd/jrd.cpp
+++ b/src/jrd/jrd.cpp
@@ -3816,6 +3816,7 @@ void JService::freeEngineData(CheckStatusWrapper* user_status)
 		validateHandle(svc);
 
 		svc->detach();
+		svc = NULL;
 	}
 	catch (const Exception& ex)
 	{