diff --git a/src/include/86box/ui.h b/src/include/86box/ui.h
index f497fb857..1c4c5aee1 100644
--- a/src/include/86box/ui.h
+++ b/src/include/86box/ui.h
@@ -34,7 +34,9 @@ extern "C" {
 #define MBX_ERROR	2
 #define MBX_QUESTION	3
 #define MBX_QUESTION_YN	4
-#define MBX_FATAL	0x20
+#define MBX_QMARK	0x10
+#define MBX_WARNING	0x20
+#define MBX_FATAL	0x40
 #define MBX_ANSI	0x80
 #define MBX_LINKS	0x100
 #define MBX_DONTASK	0x200
diff --git a/src/win/win_dialog.c b/src/win/win_dialog.c
index 16b1a2cc3..1e48b7d40 100644
--- a/src/win/win_dialog.c
+++ b/src/win/win_dialog.c
@@ -114,6 +114,9 @@ ui_msgbox_ex(int flags, void *header, void *message, void *btn1, void *btn2, voi
 			else
 				tdconfig.dwCommonButtons |= TDCBF_CANCEL_BUTTON;
 		}
+
+		if (flags & MBX_WARNING)
+			tdconfig.pszMainIcon = TD_WARNING_ICON;
 		break;
     }