diff --git a/dmenu.c b/dmenu.c
index 64ff973..11a0551 100644
--- a/dmenu.c
+++ b/dmenu.c
@@ -639,6 +639,8 @@ setup(void)
 #ifdef XINERAMA
 	i = 0;
 	if (parentwin == root && (info = XineramaQueryScreens(dpy, &n))) {
+		if (n < 1)
+			die("Xinerama reported no screens");
 		XGetInputFocus(dpy, &w, &di);
 		if (mon >= 0 && mon < n)
 			i = mon;
@@ -661,6 +663,9 @@ setup(void)
 			for (i = 0; i < n; i++)
 				if (INTERSECT(x, y, 1, 1, info[i]) != 0)
 					break;
+		/* fallback to the first screen if there is no intersection */
+		if (i >= n)
+			i = 0;
 
 		x = info[i].x_org;
 		y = info[i].y_org + (topbar ? 0 : info[i].height - mh);