title: conda update --all fails in Windows 10
body: <p>I have already checked <a href="https://stackoverflow.com/questions/40690045/conda-update-failed-in-windows-10">this question</a>, but it is not the same as the problem I am encountering.</p>
  
  <p>I just ran</p>
  
  <pre><code>C:\Users\USRNAME\Documents&gt; conda update conda
  </code></pre>
  
  <p>and the command ran without any error.  Then I attempted to run</p>
  
  <pre><code>C:\Users\USRNAME\Documents&gt; conda update --all
  </code></pre>
  
  <p>and I began to get the following error:</p>
  
  <pre><code>C:\Users\USRNAME\Documents&gt;conda update anaconda
  'C:/Program' is not recognized as an internal or external command,
  operable program or batch file.
  /Microsoft was unexpected at this time.
  
  C:\Users\USRNAME\Documents&gt;@FOR /F "delims=" %i IN ('@CALL C:/Program Files (x86)/Microsoft Visual Studio/Shared/Anaconda3_64\Scripts\conda.exe shell.cmd.exe reactivate') DO @SET "_TEMP_SCRIPT_PATH=%i"
  
  C:\Users\USRNAME\Documents&gt;
  </code></pre>
  
  <p>This has never happened before.  Usually, I am able to run <code>conda update conda</code> and <code>conda update --all</code> once a week without any kind of problem.  Any help in solving the problem would be appreciated.</p>