diff --git a/src/86box.c b/src/86box.c
index bf9be5086..7ccc3c96d 100644
--- a/src/86box.c
+++ b/src/86box.c
@@ -236,7 +236,7 @@ int efscrnsz_y = SCREEN_RES_Y;
 
 static wchar_t mouse_msg[3][200];
 
-static int do_pause_ack = 0;
+static volatile int do_pause_ack = 0;
 static volatile int pause_ack = 0;
 
 #ifndef RELEASE_BUILD