title: Can't track origin/master
body: <p>I can't add origin/master as tracking branch to the local master branch</p>
  
  <pre><code>git checkout --track origin/master
  fatal: 'origin/master' is not a commit and a branch 'master' cannot be created from it
  </code></pre>
  
  <p>My fork has some commits in it already. Remote(fork) also has 1 commit with README in it. What can be the problem?</p>
  
  <p>Edit: after running <code>git fetch origin</code>, the error message changes:</p>
  
  <pre><code>git checkout --track origin/master
  fatal: A branch named 'master' already exists.
  </code></pre>