diff --git a/tuned/plugins/plugin_scheduler.py b/tuned/plugins/plugin_scheduler.py
index 9ff7d7a..7c90592 100644
--- a/tuned/plugins/plugin_scheduler.py
+++ b/tuned/plugins/plugin_scheduler.py
@@ -246,6 +246,11 @@ class SchedulerPlugin(base.Plugin):
 					scheduler = rt[0],
 					priority = rt[1],
 					affinity = prev_affinity)
+		else:
+			if self._pid_exists(pid):
+				log.error("Refusing to tune PID %d, reading original scheduling parameters failed."
+						% pid)
+			return
 		self._set_rt(pid, self._schedcfg2param(sched), prio)
 		if affinity != "*":
 			self._set_affinity(pid, affinity)