diff --git a/pycbc/events/single.py b/pycbc/events/single.py
index 5312466fb57..f41b2dfb131 100644
--- a/pycbc/events/single.py
+++ b/pycbc/events/single.py
@@ -108,6 +108,10 @@ def verify_args(args, parser, ifos):
                 parser.error("All IFOs required in --single-ifar-est-dist "
                              "if IFO-specific options are given.")
 
+            if args.sngl_ifar_est_dist[ifo] is None:
+                # Default - no singles being used
+                continue
+
             if not args.sngl_ifar_est_dist[ifo] == 'fixed':
                 if not args.single_fit_file:
                     # Fixed IFAR option doesnt need the fits file