diff --git a/src/jrd/event.cpp b/src/jrd/event.cpp
index 2f915aaade..b3b95dfcaa 100644
--- a/src/jrd/event.cpp
+++ b/src/jrd/event.cpp
@@ -183,6 +183,7 @@ void EventManager::detach_shared_file()
 	{
 		ISC_mutex_fini(MUTEX);
 		ISC_unmap_file(local_status, &m_shmemData);
+		m_header = NULL;
 	}
 }
 
diff --git a/src/lock/lock.cpp b/src/lock/lock.cpp
index 596f28b5f4..4a373a0316 100644
--- a/src/lock/lock.cpp
+++ b/src/lock/lock.cpp
@@ -284,6 +284,7 @@ void LockManager::detach_shared_file(ISC_STATUS* status)
 	{
 		ISC_mutex_fini(MUTEX);
 		ISC_unmap_file(status, &m_shmem);
+		m_header = NULL;
 	}
 }