title: error when pushing branch into github - 'remote: error: cannot lock ref 'refs/heads/master': Unable to create'
body: <p>I get the below exception when I try to push my local branch into master</p>
  
  <pre><code>Total 0 (delta 0), reused 0 (delta 0)
  remote: error: cannot lock ref 'refs/heads/master': Unable to create '/data/c01/n08/p/vp0664/data/d-41/r-27032041/refs/heads/master.lock': File exists.
  remote: 
  remote: If no other git process is currently running, this probably means a
  remote: git process crashed in this repository earlier. Make sure no other git
  remote: process is running and remove the file manually to continue.
  </code></pre>
  
  <ul>
  <li><p>I get this exception only when pushing the master branch.</p></li>
  <li><p>I get this exception when pushing the master branch even from other computers. </p></li>
  <li><p>I get this exception even when I try to merge dev branch into master on bitbucket website directly not involving the local computer.</p></li>
  </ul>
  
  <p>Because of the above 3 reasons I don't think it is a issue with my local .git folder. I can't think of what the possible cause is.</p>
  
  <p>I have tried solutions available in answers to similar exceptions, but all of them are about cleaning/purging/manipulating the files in the .git folder but I get this same issue even from different computers and even on the bitbucket portal itself.</p>
  
  <p>Please vote for the <a href="https://bitbucket.org/site/master/issues/15209/error-when-pushing-branch-into-github" rel="nofollow noreferrer">issue</a>, if you are hitting it as well.</p>
  
  <p>PS: I am using the bitbucket.org cloud hosted option.</p>