Index: trunk/psModules/src/camera/pmReadout.c
===================================================================
--- trunk/psModules/src/camera/pmReadout.c	(revision 7017)
+++ trunk/psModules/src/camera/pmReadout.c	(revision 7311)
@@ -76,4 +76,8 @@
             readout->mask = psMemIncrRefCounter(psImageSubset(masks->data[i], *trimsec));
         }
+        if (readout->weight == NULL || readout->mask == NULL) {
+            psError(PS_ERR_UNKNOWN, false, "Trimming readout %d", i);
+            return false;
+        }
 
         // Set up the mask