diff -up hplip-3.16.5/scan.py.sourceoption hplip-3.16.5/scan.py

--- hplip-3.16.5/scan.py.sourceoption	2016-06-22 10:25:52.742799941 +0200

+++ hplip-3.16.5/scan.py	2016-06-22 10:34:51.945766487 +0200

@@ -658,6 +658,7 @@ try:

                 sys.exit(1)

         except:

             log.error("Failed to get the source from device.")

+            sys.exit(1)

         #check if device has only ADF

         if len(source_option) == 1 and 'ADF' in source_option: