title: Mercurial: "abandoned transaction found - run hg recover". Recover does not work
body: <p>Using tortoise hg on windows, I did a pull from a repository on my local drive to a repository on a usb stick.</p>
  
  <p>During the pull i guess there was a glitch in the usb-connection because it got aborted half way through.</p>
  
  <p>Now i can't pull again. I get the message: <code>abandoned transaction found - run hg recover</code></p>
  
  <p>When i run hg recover i get the following message: </p>
  
  <pre><code>rolling back interrupted transaction
  ** unknown exception encountered, details follow
  ** report bug details to http://mercurial.selenic.com/bts/
  ** or mercurial@selenic.com
  ** Python 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit (Intel)]
  ** Mercurial Distributed SCM (version 1.6.3)
  ** Extensions loaded: fixfrozenexts
  Traceback (most recent call last):
    File "hg", line 36, in &lt;module&gt;
    File "mercurial\dispatch.pyo", line 16, in run
    File "mercurial\dispatch.pyo", line 34, in dispatch
    File "mercurial\dispatch.pyo", line 54, in _runcatch
    File "mercurial\dispatch.pyo", line 494, in _dispatch
    File "mercurial\dispatch.pyo", line 355, in runcommand
    File "mercurial\dispatch.pyo", line 545, in _runcommand
    File "mercurial\dispatch.pyo", line 499, in checkargs
    File "mercurial\dispatch.pyo", line 492, in &lt;lambda&gt;
    File "mercurial\util.pyo", line 420, in check
    File "mercurial\commands.pyo", line 2869, in recover
    File "mercurial\localrepo.pyo", line 606, in recover
    File "mercurial\transaction.pyo", line 173, in rollback
  ValueError: too many values to unpack
  </code></pre>
  
  <p>If i try to rollback manually i get this message: <code>no rollback information available</code></p>
  
  <p>This time i can quite easily just delete the whole backup on my stick and do a fresh pull because the repo is small and the usb-stick does not contain any other changes. But what if this happens on a larger repo where i can't afford to restart from scratch? How can i recover the repo?</p>