Index: trunk/ppStack/src/ppStackMatch.c
===================================================================
--- trunk/ppStack/src/ppStackMatch.c	(revision 17682)
+++ trunk/ppStack/src/ppStackMatch.c	(revision 17696)
@@ -37,4 +37,9 @@
     int renormWidth = psMetadataLookupS32(&mdok, config->arguments,
                                           "RENORM.WIDTH"); // Width for renormalisation box
+
+    if (!pmReadoutMaskNonfinite(readout, maskBad)) {
+        psError(PS_ERR_UNKNOWN, false, "Unable to mask non-finite pixels in readout.");
+        return false;
+    }
 
     if (psMetadataLookupBool(&mdok, config->arguments, "HAVE.PSF")) {