virtualenvで仮想環境構築時のUnicodeDecodeError

virtualenvでvirtualenv　env1として仮想環境を作成しようとしたところ、

PS C:\lessonfield\kaki_kdjango> virtualenv env1
Using base prefix 'c:\anaconda'
  No LICENSE.txt / LICENSE found in source
New python executable in C:\lessonfield\kaki_kdjango\env1\Scripts\python.exe
Installing setuptools, pip, wheel...
done.
Traceback (most recent call last):
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 939, in call_subprocess
    line = line.decode(encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x95 in position 38: invalid start byte

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\anaconda\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "c:\anaconda\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Anaconda\Scripts\virtualenv.exe\__main__.py", line 7, in <module>
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 870, in main
    symlink=options.symlink,
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 1179, in create_environment
    install_wheel(to_install, py_executable, search_dirs, download=download)
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 1023, in install_wheel
    _install_wheel_with_search_dir(download, project_names, py_executable, search_dirs)
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 1116, in _install_wheel_with_search_dir
    call_subprocess(cmd, show_stdout=False, extra_env=env, stdin=script)
  File "c:\anaconda\lib\site-packages\virtualenv.py", line 941, in call_subprocess
    line = line.decode(fs_encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x95 in position 38: invalid start byte