Index: trunk/ppStack/src/ppStackLoop.c
===================================================================
--- trunk/ppStack/src/ppStackLoop.c	(revision 18490)
+++ trunk/ppStack/src/ppStackLoop.c	(revision 18507)
@@ -592,5 +592,6 @@
             pmReadoutFreeData(ro);
 
-            psLogMsg("ppStack", PS_LOG_INFO, "%ld total pixels to inspect from image %d", inspect->n, i);
+            psLogMsg("ppStack", PS_LOG_INFO, "%ld total pixels to inspect from image %d",
+                     inspect ? inspect->n : 0, i);
 
             psPixels *reject = pmStackReject(inspect, NULL, threshold, subRegions->data[i],