title: Git rename from index.lock to index failed
body: <p>Using the GitHub Windows client I did a <em>sync</em> to pull remote changes to my local machine, but before finishing the sync, I ran out of disk space and the sync failed.  Now I seem to have a bunch of local changes that are actually changes that were being pulled from origin.  I tried to run git pull but got:</p>
  
  <pre><code>C:\Users\Tom\SourceLog [master +4 ~26 -0 !]&gt; git pull
  Updating b3a86e1..5afd74f
  error: Your local changes to the following files would be overwritten by merge:
          SourceLog.Interface/IChangedFile.cs
          SourceLog.Interface/ILogEntry.cs
          ...
  Please, commit your changes or stash them before you can merge.
  error: The following untracked working tree files would be overwritten by merge:
          Lib/MSBuildExtensionPack/4.0.6.0/Ionic.Zip.dll
          Lib/MSBuildExtensionPack/4.0.6.0/MSBuild.ExtensionPack.dll
          ...
  Aborting
  </code></pre>
  
  <p>So now I'm trying to discard the local changes but I'm getting:</p>
  
  <pre><code>C:\Users\Tom\SourceLog [master +4 ~26 -0 !]&gt; git checkout -- .
  Rename from '.git/index.lock' to '.git/index' failed. Should I try again? (y/n) y
  Rename from '.git/index.lock' to '.git/index' failed. Should I try again? (y/n) n
  fatal: unable to write new index file
  </code></pre>
  
  <p>How can I clean this up?  (I didn't have any local changes before starting the sync.)</p>
  
  <h2>Update</h2>
  
  <p>Can't seem to reset head..</p>
  
  <pre><code>C:\Users\Tom\SourceLog [master +4 ~0 -0 !]&gt; git reset head
  Rename from '.git/index.lock' to '.git/index' failed. Should I try again? (y/n) y
  Rename from '.git/index.lock' to '.git/index' failed. Should I try again? (y/n) n
  error: Could not write new index file.
  fatal: Could not reset index file to revision 'head'.
  </code></pre>