Index: trunk/psModules/src/camera/pmFPAMaskWeight.c
===================================================================
--- trunk/psModules/src/camera/pmFPAMaskWeight.c	(revision 19163)
+++ trunk/psModules/src/camera/pmFPAMaskWeight.c	(revision 20095)
@@ -212,4 +212,8 @@
     if (!mdok || isnan(readnoise)) {
         psError(PS_ERR_IO, true, "CELL.READNOISE is not set --- unable to set weight.\n");
+        return false;
+    }
+    if (psMetadataLookup(cell->concepts, "CELL.READNOISE.UPDATE")) {
+        psError(PS_ERR_IO, true, "CELL.READNOISE has not yet been updated for the gain");
         return false;
     }