documentclass{book}
usepackage{xcolor}
usepackage{tcolorbox}

begin{document}

    tcolorbox[%
    title=Title of Box]%
    Test%
    endtcolorbox%
end{document}

! Undefined control sequence.
pgfutil@colorlet ->colorlet

l.113 pgfutil@colorlet
                       {pgftransparent}{black}