diff --git a/scwx-qt/source/scwx/qt/map/alert_layer.cpp b/scwx-qt/source/scwx/qt/map/alert_layer.cpp
index 93a6d2d1..156b1a6d 100644
--- a/scwx-qt/source/scwx/qt/map/alert_layer.cpp
+++ b/scwx-qt/source/scwx/qt/map/alert_layer.cpp
@@ -11,6 +11,7 @@
 #include <mutex>
 #include <ranges>
 #include <set>
+#include <shared_mutex>
 #include <unordered_map>
 #include <unordered_set>