From Chris Cromer, 3 Weeks ago, written in Plain Text.
This paste will give up the ghost in 10 Months.
  1. <div><strong>&lt;class 'TypeError'&gt;</strong></div><div>No registered converter was able to produce a C++ rvalue of type std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt; from this Python object of type NoneType</div><div><br/>Traceback:</div><div><pre>File &quot;/usr/lib/calamares/modules/displaymanager/;, line 1080, in run
  2.     dm_message = dm.set_autologin(username, do_autologin, default_desktop_environment)
  4.   File &quot;/usr/lib/calamares/modules/displaymanager/;, line 646, in set_autologin
  5.     libcalamares.utils.target_env_call(</pre></div>