I am trying to compile a .tex document into a pdf in TexStudio (and I have also tried in MikTex) and the following error is outputted File l3backend-pdfmode.def not found
. I have tried downloading 13backend package but no luck. Do I need to place the package in a specific folder?
I had the same problem, turned out my miktex library was out-of-date
I opened "miktex console" and updated it.