I have the following tex file:




\setmainfont{Liberation Serif} 
\newfontfamily\greekfont[Script=Greek]{Linux Libertine O}
\newfontfamily\greekfontsf[Script=Greek]{Linux Libertine O}
\setmainfont[Kerning=On,Mapping=tex-text]{Linux Libertine O}

\title{Tο μικρό γλυκό πρωτόκολλο WPA-PSK}
\author{Τσακ Νόρις}



   \chapter{Επίθεση σε οικιακό δίκτυο Wi-Fi που χρησιμοποιεί WPA2-CCMP-PSK}
   \section{Εργαλεία Επίθεσης}
   Προκειμένου να εκτελεστεί η επίθεση, χρησιμοποιήσαμε το εργαλείο \texttt{airchack-ng} σε \texttt{Kubuntu Linux 16.04 lts}. Λαλαλαλα θα τα σπάσω όλα.

And I noticed that there is some mysterious characters for space as you can see in image: Rendered Tex

In my case is the character: Weird Character

I Use TexStudio on Ubuntu 16.04. If you want to check it out I recommend using this link to download it.

  • 1
    with pretest TeXLive 2018 on Ubuntu 16.04 I do not get the mysterious character after copying pasting the code in an Emacs buffer and compiling from there.
    – user4686
    Commented Apr 17, 2018 at 11:50
  • but log contains Missing character: There is no   in font Linux Libertine O/OT:script=grek;langu where the character is Unicode IDEOGRAPHIC SPACE, #xE3 #x80 #x80 (encoded by coding system utf-8-unix) U+3000
    – user4686
    Commented Apr 17, 2018 at 11:53
  • the big space character is in input... just delete it (after the end of sentence mark)...
    – user4686
    Commented Apr 17, 2018 at 11:53
  • 1
    That's the /.notdef character. You get it (but not with every font) if you use a glyph that isn't in the font. Beside this: You are overdoing with xltxtra, fontspec, libertine, xunicode. Only libertine should be enough. Commented Apr 17, 2018 at 11:54
  • So if I use a different font I can display it correctly right? Commented Apr 17, 2018 at 11:55

1 Answer 1


You have a spurious space U+3000 IDEOGRAPHIC SPACE between the period after lts} and Λαλαλαλα.

If I paste the text in https://r12a.github.io/app-conversion/ and click “Convert”, the box HTML/XML shows

\texttt{Kubuntu Linux 16.04 lts}. Λαλαλαλα

You should remove the offending character or do

\newunicodechar{^^^^3000}{ }

(but getting rid of the character is better).

By the way, you should no longer load xltxtra and xunicode.

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