https://github.com/mate-desktop/mate-applets/issues/193

--- gnome-applets-3.20.0/cpufreq/src/cpufreq-monitor-libcpufreq.c	2016-03-10 16:53:48.000000000 -0600
+++ gnome-applets-3.20.0/cpufreq/src/cpufreq-monitor-libcpufreq.c	2016-09-12 17:46:30.581654843 -0500
@@ -23,6 +23,7 @@
 
 #include <stdlib.h>
 #include <cpufreq.h>
+#include <cpuidle.h>
 
 #include "cpufreq-monitor-libcpufreq.h"
 #include "cpufreq-utils.h"
@@ -110,7 +111,7 @@
 		/* Check whether it failed because
 		 * cpu is not online.
 		 */
-		if (!cpufreq_cpu_exists (cpu)) {
+		if (cpupower_is_cpu_online (cpu)) {
 			g_object_set (G_OBJECT (monitor), "online", FALSE, NULL);
 			return TRUE;
 		}