--- a/build/moz.configure/init.configure
+++ b/build/moz.configure/init.configure
@@ -198,17 +198,16 @@ option(env='PYTHON', nargs=1, help='Pyth
 
 
 @depends('PYTHON', check_build_environment, mozconfig, '--help')
 @imports('os')
 @imports('sys')
 @imports('subprocess')
 @imports(_from='mozbuild.configure.util', _import='LineIO')
 @imports(_from='mozbuild.virtualenv', _import='VirtualenvManager')
-@imports(_from='mozbuild.virtualenv', _import='verify_python_version')
 @imports('distutils.sysconfig')
 def virtualenv_python(env_python, build_env, mozconfig, help):
     if help:
         return
 
     python = env_python[0] if env_python else None
 
     # Ideally we'd rely on the mozconfig injection from mozconfig_options,
@@ -219,18 +218,38 @@ def virtualenv_python(env_python, build_
             python = mozconfig['env']['added']['PYTHON']
         elif 'PYTHON' in mozconfig['env']['modified']:
             python = mozconfig['env']['modified']['PYTHON'][1]
         elif 'PYTHON' in mozconfig['vars']['added']:
             python = mozconfig['vars']['added']['PYTHON']
         elif 'PYTHON' in mozconfig['vars']['modified']:
             python = mozconfig['vars']['modified']['PYTHON'][1]
 
-    with LineIO(lambda l: log.error(l)) as out:
-        verify_python_version(out)
+    minimum_version = Version('2.7.3')
+    major, minor, micro = sys.version_info[:3]
+    our_version = Version('%d.%d.%d' % (major, minor, micro))
+
+    if major != 2 or our_version < minimum_version:
+        msg = ('Python %s or greater (but not Python 3) is required to build. '
+              'You are running Python %s. ' % (minimum_version, our_version))
+
+        if os.name == 'nt':
+            msg += ('Please upgrade to the latest MozillaBuild development '
+                   'environment. See https://developer.mozilla.org/en-US/docs/Developer_Guide/Build_Instructions/Windows_Prerequisites')
+        else:
+            msg += ('Run `mach bootstrap` to ensure your system is up to date. '
+                   'If you still receive this error afterwards, your shell '
+                   'environment is likely detecting another Python version. '
+                   'Ensure a modern Python can be found in the paths defined '
+                   'by the $PATH environment variable. Or set the PYTHON '
+                   'environment or mozconfig variable to specify which Python '
+                   'interpreter to use.')
+
+        die(msg)
+
     topsrcdir, topobjdir = build_env.topsrcdir, build_env.topobjdir
     if topobjdir.endswith('/js/src'):
         topobjdir = topobjdir[:-7]
 
     with LineIO(lambda l: log.info(l), 'replace') as out:
         manager = VirtualenvManager(
             topsrcdir, topobjdir,
             os.path.join(topobjdir, '_virtualenv'), out,

--- a/python/mozbuild/mozbuild/virtualenv.py
+++ b/python/mozbuild/mozbuild/virtualenv.py
@@ -15,34 +15,16 @@ import sys
 import warnings
 
 from distutils.version import LooseVersion
 
 IS_NATIVE_WIN = (sys.platform == 'win32' and os.sep == '\\')
 IS_MSYS2 = (sys.platform == 'win32' and os.sep == '/')
 IS_CYGWIN = (sys.platform == 'cygwin')
 
-# Minimum version of Python required to build.
-MINIMUM_PYTHON_VERSION = LooseVersion('2.7.3')
-MINIMUM_PYTHON_MAJOR = 2
-
-
-UPGRADE_WINDOWS = '''
-Please upgrade to the latest MozillaBuild development environment. See
-https://developer.mozilla.org/en-US/docs/Developer_Guide/Build_Instructions/Windows_Prerequisites
-'''.lstrip()
-
-UPGRADE_OTHER = '''
-Run |mach bootstrap| to ensure your system is up to date.
-
-If you still receive this error, your shell environment is likely detecting
-another Python version. Ensure a modern Python can be found in the paths
-defined by the $PATH environment variable and try again.
-'''.lstrip()
-
 
 class VirtualenvManager(object):
     """Contains logic for managing virtualenvs for building the tree."""
 
     def __init__(self, topsrcdir, topobjdir, virtualenv_path, log_handle,
         manifest_path):
         """Create a new manager.
 
@@ -520,42 +502,21 @@ class VirtualenvManager(object):
         # against the executing interpreter. By creating a new process, we
         # force the virtualenv's interpreter to be used and all is well.
         # It /might/ be possible to cheat and set sys.executable to
         # self.python_path. However, this seems more risk than it's worth.
         subprocess.check_call([os.path.join(self.bin_path, 'pip')] + args,
             stderr=subprocess.STDOUT)
 
 
-def verify_python_version(log_handle):
-    """Ensure the current version of Python is sufficient."""
-    major, minor, micro = sys.version_info[:3]
-
-    our = LooseVersion('%d.%d.%d' % (major, minor, micro))
-
-    if major != MINIMUM_PYTHON_MAJOR or our < MINIMUM_PYTHON_VERSION:
-        log_handle.write('Python %s or greater (but not Python 3) is '
-            'required to build. ' % MINIMUM_PYTHON_VERSION)
-        log_handle.write('You are running Python %s.\n' % our)
-
-        if os.name in ('nt', 'ce'):
-            log_handle.write(UPGRADE_WINDOWS)
-        else:
-            log_handle.write(UPGRADE_OTHER)
-
-        sys.exit(1)
-
-
 if __name__ == '__main__':
     if len(sys.argv) < 5:
         print('Usage: populate_virtualenv.py /path/to/topsrcdir /path/to/topobjdir /path/to/virtualenv /path/to/virtualenv_manifest')
         sys.exit(1)
 
-    verify_python_version(sys.stdout)
-
     topsrcdir, topobjdir, virtualenv_path, manifest_path = sys.argv[1:5]
     populate = False
 
     # This should only be called internally.
     if sys.argv[1] == 'populate':
         populate = True
         topsrcdir, topobjdir, virtualenv_path, manifest_path = sys.argv[2:]