Cannot run minimal example of tcolorbox

Question

I am using the minimal example provided by many users, to import the tcolorbox package:

\documentclass{article}
\usepackage[all]{tcolorbox}

\begin{document}
Hello 
\end{document}

Couldn't be any simpler, really. But I am getting the error:

Undefined control sequence: \ExplSyntaxOn
Undefined control sequence: \ExplSyntaxOff

when compiling with pdfLatex. I am using latest versions of everything. My IDE is TexStudio.

What's wrong with this?

Answer 1

Most likely you have an older LaTeX that does not pre-load expl3. So you need

\usepackage{expl3}

before

\usepackage{tcolorbox}

Answer 2

\documentclass{article}
\usepackage[most]{tcolorbox}

\begin{document}
    Hello 
\end{document}

OR

\documentclass{article}
\usepackage[most]{tcolorbox}

\begin{document}
\begin{tcolorbox}
    This is a \textbf{tcolorbox}.
\end{tcolorbox}
\end{document}