Index: trunk/ppViz/src/ppVizPSF/ppVizPSFLoop.c
===================================================================
--- trunk/ppViz/src/ppVizPSF/ppVizPSFLoop.c	(revision 27665)
+++ trunk/ppViz/src/ppVizPSF/ppVizPSFLoop.c	(revision 27666)
@@ -134,6 +134,11 @@
                     psLogMsg("ppVizPSF", PS_LOG_INFO, "Generating %dx%d image with single PSF",
                              numCols, numRows);
+
                     psRegion *trimsec = psMetadataLookupPtr(NULL, cell->concepts, "CELL.TRIMSEC");
                     *trimsec = psRegionSet(0, numCols, 0, numRows);
+
+                    // We have trouble with PSF residuals in this case, so don't use them
+                    psFree(psf->residuals);
+                    psf->residuals = NULL;
                 }