diff --git a/fan-speed-control.pl b/fan-speed-control.pl
index db073b4..8a8bfcf 100755
--- a/fan-speed-control.pl
+++ b/fan-speed-control.pl
@@ -201,7 +201,7 @@ while () {
     # could just be a simple pipe, but hddtemp has a strong posibility
     # to be stuck in a D state, and hold STDERR open despite a kill
     # -9, so instead just send it to a tempfile, and read from that tempfile
-    system("timeout -k 1 20 hddtemp /dev/sd? > $tempfilename");
+    system("timeout -k 1 20 hddtemp /dev/sd? | grep -v 'not available' > $tempfilename");
     @hddtemps=`cat < $tempfilename`;
   }
   if (!@ambient_ipmitemps) {