title: Cannot perform operation. Computing alternate solutions, may take a while STS?
body: <p>I would like to ask what does this error mean when adding a new <code>Available Software Site</code> and installing new software in Eclipse/STS (Spring Tool Suite) using <code>Install New Software</code>?</p>
  
  <p>I am experiencing this problem with the <code>Spring Tool Suite Nightly Build</code>:</p>
  
  <p><a href="http://dist.springsource.com/snapshot/STS/nightly-distributions.html" rel="noreferrer">http://dist.springsource.com/snapshot/STS/nightly-distributions.html</a></p>
  
  <p>I am trying to update my STS and reinstall the <code>Welcome Dashboard</code>. When I try to add the following <code>Available Software Site</code>:</p>
  
  <p><code>http://dist.springsource.com/snapshot/TOOLS/nightly/e4.5</code></p>
  
  <p>I select all the items in order that they all will be installed,</p>
  
  <p>Then this message is shown in the progress indicator:</p>
  
  <blockquote>
    <p>Cannot perform operation. Computing alternate solutions, may take a while. </p>
  </blockquote>
  
  <p>Sometimes I get this message even when trying to update something.</p>
  
  <p>What does it mean? That I have some items already installed? That there's a problem contacting the site?</p>