Index: trunk/psModules/src/detrend/pmShutterCorrection.c
===================================================================
--- trunk/psModules/src/detrend/pmShutterCorrection.c	(revision 27818)
+++ trunk/psModules/src/detrend/pmShutterCorrection.c	(revision 27832)
@@ -1015,11 +1015,15 @@
 
         pmShutterCorrection *corr = pmShutterCorrectionFullFit(newtimes, newcounts, newerrors, guess); // The actual correction
-        psTrace("psModules.detrend", 5, "Shutter correction fit: scale: %f, offset: %f, offref: %f\n", corr->scale, corr->offset, corr->offref);
-
-        if (corr && isfinite(corr->offref) && corr->valid) {
-            psTrace("psModules.detrend", 5, "Sample reference value: %f\n", corr->offref);
-            meanRef += corr->offref;
-            numGood++;
-        }
+
+        if (corr) {
+	    psTrace("psModules.detrend", 5, "Shutter correction fit: scale: %f, offset: %f, offref: %f\n", corr->scale, corr->offset, corr->offref);
+	    if (isfinite(corr->offref) && corr->valid) {
+		psTrace("psModules.detrend", 5, "Sample reference value: %f\n", corr->offref);
+		meanRef += corr->offref;
+		numGood++;
+	    }
+        } else {
+	    psTrace("psModules.detrend", 5, "failed Shutter correction fit\n");
+	}
 
         psFree(corr);