--- a/python/mozboot/mozboot/bootstrap.py
+++ b/python/mozboot/mozboot/bootstrap.py
@@ -7,16 +7,17 @@ from __future__ import print_function
 
 import platform
 import sys
 import os
 import subprocess
 
 # Don't forgot to add new mozboot modules to the bootstrap download
 # list in bin/bootstrap.py!
+from mozboot.base import MODERN_RUST_VERSION
 from mozboot.centosfedora import CentOSFedoraBootstrapper
 from mozboot.debian import DebianBootstrapper
 from mozboot.freebsd import FreeBSDBootstrapper
 from mozboot.gentoo import GentooBootstrapper
 from mozboot.osx import OSXBootstrapper
 from mozboot.openbsd import OpenBSDBootstrapper
 from mozboot.archlinux import ArchlinuxBootstrapper
 from mozboot.windows import WindowsBootstrapper
@@ -278,16 +279,18 @@ class Bootstrapper(object):
             if dest:
                 dest = os.path.expanduser(dest)
                 have_clone = clone_firefox(self.instance.which('hg'), dest)
 
         if not have_clone:
             print(SOURCE_ADVERTISE)
 
         print(self.finished % name)
+        if not (self.instance.which('rustc') and self.instance._parse_version('rustc') >= MODERN_RUST_VERSION):
+            print("To build %s, please restart the shell (Start a new terminal window)" % name)
 
         # Like 'suggest_browser_mozconfig' or 'suggest_mobile_android_mozconfig'.
         getattr(self.instance, 'suggest_%s_mozconfig' % application)()
 
 
 def update_vct(hg, root_state_dir):
     """Ensure version-control-tools in the state directory is up to date."""
     vct_dir = os.path.join(root_state_dir, 'version-control-tools')