diff --git a/src/zm_db.cpp b/src/zm_db.cpp
index cc0797c12..76bd04e27 100644
--- a/src/zm_db.cpp
+++ b/src/zm_db.cpp
@@ -238,8 +238,13 @@ zmDbQueue::~zmDbQueue() {
 }
 
 void zmDbQueue::stop() {
-  mTerminate = true;
-  mCondition.notify_all();
+  {
+    std::unique_lock<std::mutex> lock(mMutex);
+
+    mTerminate = true;
+    mCondition.notify_all();
+  }
+
   if (mThread.joinable()) mThread.join();
 }