diff --git a/src/server/shared/Debugging/WheatyExceptionReport.h b/src/server/shared/Debugging/WheatyExceptionReport.h
index ef6334add16..8c2479d5232 100644
--- a/src/server/shared/Debugging/WheatyExceptionReport.h
+++ b/src/server/shared/Debugging/WheatyExceptionReport.h
@@ -7,6 +7,7 @@
 #include <set>
 #include <stdlib.h>
 #include <stack>
+#include <mutex>
 #define countof  _countof
 
 #define WER_MAX_ARRAY_ELEMENTS_COUNT 10