diff --git a/0.73_My_PuTTY/pageant.c b/0.73_My_PuTTY/pageant.c
index 8d29faf..292e52f 100644
--- a/0.73_My_PuTTY/pageant.c
+++ b/0.73_My_PuTTY/pageant.c
@@ -183,7 +183,7 @@ static int confirm_key_usage(char* fingerprint, char* comment) {
 		)
 		) )
 	{
-		result = MessageBox(NULL, message, title, MB_ICONQUESTION | MB_YESNO);
+		result = MessageBox(NULL, message, title, MB_ICONQUESTION | MB_YESNO | MB_SYSTEMMODAL);
 	}
 
 	if (result != IDYES) {