I'm using cleanthesis template and have trouble in to compile since KOMA-script and titlesec are not compatible

Then, the idea would be to "translate" the titlesec section:

\titleformat{\chapter}[display]%
{\usekomafont{chapter}}%
{\vspace{-8em}\raggedleft{%
{\color{ctcolorchapterline}%
{\color{ctcolorchapternum}
\fontsize{60}{60}\selectfont\thechapter}% Chapter number
}%
}%
{-2.1em}%
{\ctformatchapter}%
[\phantomsection]


into a KOMA-script one, that I tried:

\renewcommand*{\chapterformat}{%
\vspace{-8em}\raggedleft{%
{\color{ctcolorchapterline}%
{\color{ctcolorchapternum}
\fontsize{60}{60}\selectfont \thechapter \autodot\endskip}% Chapter number
}%
}


What I would like is:

What I have:

Thank you.

• I once stood at the exact same point, but I took the other road and switched to book class - so I could keep the titelsec definitions. I did not regret it in the last two or so years. – samcarter_is_at_topanswers.xyz Nov 22 '16 at 18:39
• But why are you asking the same question two times? – samcarter_is_at_topanswers.xyz Nov 22 '16 at 18:40

The linked cleanthesis package uses KOMA-Script commands. So it should be used with a KOMA-Script class but it breaks many of their features. For example listof=totoc does not work with cleanthesis.

\documentclass{scrbook}[2015/10/03]
\usepackage{lmodern}
\usepackage{xcolor}
\definecolor{ctcolorchapternum}{cmyk}{.48, .05, .91, 0}
\colorlet{ctcolorchapterline}{ctcolorchapternum}

\RedeclareSectionCommand[
beforeskip=1sp,
font=\huge\mdseries
]{chapter}

\renewcommand*\chapterformat{%
\smash{\textcolor{ctcolorchapterline}{\rule[-5pt]{2pt}{10cm}}}%
\textcolor{ctcolorchapternum}{\fontsize{60pt}{60pt}\selectfont\thechapter}%
}%

\renewcommand*\chapterlinesformat[3]{%
\parbox[t]{\dimexpr\textwidth-2em\relax}{\raggedchapter #3}%
\hfill
\makebox[0pt][l]{#2}%
}

\usepackage{blindtext}
\begin{document}
\tableofcontents
\blinddocument
\chapter{This is a really long chapter title, so there is a line break}
\end{document}


Or if you use option b instead t for \parbox:

If you really want to use classicthesis you can add the following code between \usepackage{classicthesis} and \begin{document} in the file thesis-example.tex of your linked example:

\KOMAoptions{chapterprefix=false}
\RedeclareSectionCommand[
beforeskip=1sp,
font=\huge\mdseries
]{chapter}

\renewcommand*\chapterformat{%
\smash{\textcolor{ctcolorchapterline}{\rule[-5pt]{2pt}{10cm}}}%

Note that you also can simple remove chapterprefix=true from the class options instead using \KOMAoptions{chapterprefix=false}.