diff --git a/src/86box.c b/src/86box.c
index f675f4940..bf9be5086 100644
--- a/src/86box.c
+++ b/src/86box.c
@@ -237,7 +237,7 @@ int efscrnsz_y = SCREEN_RES_Y;
 static wchar_t mouse_msg[3][200];
 
 static int do_pause_ack = 0;
-static int pause_ack = 0;
+static volatile int pause_ack = 0;
 
 #ifndef RELEASE_BUILD
 static char buff[1024];