Package xcolor Error: Undefined colors “Maroon”/“Royal Blue” when master has PDF included classicthesis 3.1

I also encountered this problem and found the following solution.

This problem is caused by the pdfpages package that itself load the xcolor package with no option, while the problematic colors are defined in the dvipsnames option of the xcolor package. This 'bug' is described in 'Pitfalls' section of the pdfpages manual.

The solution to these, explained in the manual, is to load the xcolor package with the dvipsnames option before the pdfpages package. Which is actually done by classicthesis.sty.

The problem is that when you use the Lyx internal PDF include, it load the pdfpages package before any user supplied options. So the only workaround is not to use the Lyx PDF include.

Declare the \usepackage{pdfpages} in preamble and then include the pdf through the \includepdf[<key=val>]{<filename>} in an evil red text in latex.

Another workaround is to add the desired xcolor options in the document class definition

\documentclass[...,table,usenames,dvipsnames]{...}

I also encountered this problem but for me just uncommenting \definecolor for Maroon, RoyalBlue and Black resolves the issue.

I'm using classicthesis from the italian package of Lorenzo Pantieri.