I have a problem compiling documents - if I use expl3 package, I get an error l3backend error saying ! LaTeX Error: File l3backend-pdfmode.def' not found. My problem is that installing l3backend package (as suggested as an answer to this question) does not resolve the problem. I tried installing the package the same way as all my packages - using \usepackage{l3backend} in my document like this

\documentclass{article}
\usepackage{expl3}
\usepackage{l3backend}

\begin{document}
Hi!
\end{document}


I get no windows asking me for package installation permission as I usually do when including a new package and I keep getting the same error. What am I doing wrong?

• install the l3backend package with the package manager of your tex system. – Ulrike Fischer Jul 9 at 13:47
• your mention of a "window" probably means that you are using miktex. In this case update the package data base in the miktex console. There is an icon "Update DB" above the list of packages. – Ulrike Fischer Jul 9 at 13:57
• And you should never \usepackage{l3backend}. The correct backend package is selected automatically by expl3: loading it manually will usually be wrong. – Phelype Oleinik Jul 9 at 14:01

And also deleted \usepackage{l3backend}` from my code as Phelype suggested. That solved it. Thanks