--- a/build-aux/pre-inst-env.in
+++ b/build-aux/pre-inst-env.in
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2012, 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
+# Copyright © 2012, 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
 #
 # This file is part of GNU Guix.
 #
@@ -68,4 +68,11 @@ export NIX_HASH
 GUIX_UNINSTALLED=1
 export GUIX_UNINSTALLED
 
+guix="$abs_top_builddir/scripts/guix"
+if [ ! -x "$guix" ]
+then
+    echo "'$guix' is missing, please run 'make'." >&2
+    exit 1
+fi
+
 exec "$@"