diff --git a/libretroshare/src/tor/PendingOperation.h b/libretroshare/src/tor/PendingOperation.h
index 5115f3252..cec170f9e 100644
--- a/libretroshare/src/tor/PendingOperation.h
+++ b/libretroshare/src/tor/PendingOperation.h
@@ -33,6 +33,7 @@
 #pragma once
 
 #include <functional>
+#include <string>
 
 /* Represents an asynchronous operation for reporting status
  *