Index: trunk/psModules/src/camera/pmHDUGenerate.c
===================================================================
--- trunk/psModules/src/camera/pmHDUGenerate.c	(revision 7168)
+++ trunk/psModules/src/camera/pmHDUGenerate.c	(revision 7254)
@@ -26,5 +26,7 @@
     for (int i = 0; i < cells->n; i++) {
         pmCell *cell = cells->data[i];  // A cell
-        result |= psListAdd(list, PS_LIST_TAIL, cell);
+        if (!cell->hdu) {               // Don't add cells that have their own HDU
+            result |= psListAdd(list, PS_LIST_TAIL, cell);
+        }
     }
 
@@ -44,5 +46,7 @@
     for (int i = 0; i < chips->n; i++) {
         pmChip *chip = chips->data[i];  // A chip
-        result |= addCellsFromChip(list, chip);
+        if (! chip->hdu) {              // Don't add chips that have their own HDU
+            result |= addCellsFromChip(list, chip);
+        }
     }
 
@@ -263,5 +267,5 @@
     }
     if (numReadouts == 0 || type == 0) {
-        psError(PS_ERR_IO, true, "Unable to find images within HDU.\n");
+        // Nothing from which to create an HDU
         psFree(cells);
         return false;