diff --git a/guix/scripts/challenge.scm b/guix/scripts/challenge.scm
index 590d8f1099..9ab4fbe2a9 100644
--- a/guix/scripts/challenge.scm
+++ b/guix/scripts/challenge.scm
@@ -118,7 +118,7 @@ (define (select-reference item narinfos urls)
               (select-reference item narinfos urls)
               (narinfo-hash->sha256 (narinfo-hash first))))))
       (()
-       (leave (_ "no substitutes for '~a'~%") item))))
+       (warning (_ "no substitutes for '~a'; cannot conclude~%") item))))
 
   (mlet* %store-monad ((local     (mapm %store-monad
                                         query-locally-built-hash items))