title: Why I am suddenly seeing `Usage: source deactivate` whenever I run virtualenvwrapper commands?
body: <p>I never used to see this message before when using virtualenvwrapper, but now I'm suddenly seeing this message whenever I run, say, <code>mkvirtualenv &lt;environment&gt;</code> or <code>workon &lt;environment&gt;</code>:</p>
  
  <pre><code>Usage: source deactivate
  
  removes the 'bin' directory of the environment activated with 'source
  activate' from PATH. 
  </code></pre>
  
  <p>I haven't modified virtualenvwrapper at all, and a quick google search only yields <a href="https://github.com/ContinuumIO/conda/issues/276" rel="noreferrer">this GitHub issue</a> -- I did install IPython/Anaconda a while back, but I'm not sure how it might be interfering with virtualenvwrapper. In any case, I tried updating both (<code>conda update conda; conda update ipython</code>), as well as updating virtualenvwrapper itself to v4.1.1, but I'm still seeing this error. </p>
  
  <p>I'm running OS X 10.8.4.</p>