title: Cannot install plv8 for Postgres 12 on Windows
body: <p>I have downloaded the plv8 installation package from xTuple using <a href="http://updates.xtuple.com/updates/plv8/win/xtuple_plv8.zip" rel="nofollow noreferrer">this link</a>.
  I have run the installation batch file in that package.
  I've checked the relevant files are now in bin, lib and share/extension.</p>
  <p>I have given my user superuser permissions with:</p>
  <pre><code>ALTER USER administrator WITH superuser
  </code></pre>
  <p>When I try to create the extension, I receive a Permission Denied error:</p>
  <pre><code>CREATE EXTENSION IF NOT EXISTS plv8
  &gt; ERROR:  could not open extension control file &quot;C:/Program Files/PostgreSQL/12/share/extension/plv8.control&quot;: Permission denied
  </code></pre>
  <p>I can't work out what's wrong.</p>