VirtualEnv DistributionNotFound

事緣: 原打算建立一個新的 Python no-site-package 環境

virtualenv --no-site-package ~/Venv/[project]

誰不知在升級 Lion 之後加上種種原因就出現了這種情況

Traceback (most recent call last):
  File "/usr/local/bin/virtualenv", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 2603, in </module><module>
    working_set.require(__requires__)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 666, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 565, in resolve
    raise DistributionNotFound(req)  # XXX put more info here
pkg_resources.DistributionNotFound: virtualenv==1.5.1
</module>

最後問了問大神.可是卻得不到比較好的解決方法.連中文資料也沒有.
再者根據 Stackoverflow 的提示.終於解決了.方法就是重新安裝 virtualenv
至於為何要用 sudo.最主要省去 sudo 時會有權限問題.(應該是自己改了不應改的東西)

sudo easy_install virtualenv

# 成功了
virtualenv --no-site-package ~/Venv/[project]