Index: trunk/ppStack/src/ppStackPhotometry.c
===================================================================
--- trunk/ppStack/src/ppStackPhotometry.c	(revision 20751)
+++ trunk/ppStack/src/ppStackPhotometry.c	(revision 20777)
@@ -145,4 +145,11 @@
     }
 
+    if (!pmFPAfileDropInternal(config->files, "PSPHOT.BACKMDL") ||
+        !pmFPAfileDropInternal (config->files, "PSPHOT.BACKMDL.STDEV") ||
+        !pmFPAfileDropInternal (config->files, "PSPHOT.BACKGND")) {
+        psError(PS_ERR_UNKNOWN, false, "Unable to drop PSPHOT internal files.");
+        return false;
+    }
+
     pmFPAfileActivate(config->files, false, "PSPHOT.INPUT");