Q:

File l3backend-pdfmode.def not found when loading expl3 alternative solution

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? 

A:

I followed Ulrike's comment.  

In this case update the package data base in the miktex console.  There is an icon "Update DB" above the list of packages. 

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

