R check warning: Files in the 'vignettes' directory but no files in 'inst/doc'
I had a similar issue with an Rmd vignette. I fixed it by changing the YAML header of the vignette to something like this:
---
author: "Name Surname"
date: "`r Sys.Date()`"
output: rmarkdown::html_vignette
vignette: >
%\VignetteEngine{knitr::knitr}
%\VignetteIndexEntry{Title of your vignette}
%\usepackage[UTF-8]{inputenc}
---
I fixed the problem with adding the .pdf output of my Vignette to inst/doc
Although I am not sure, if this is the supposed solution, it made the warning disappear.
In my case, I was getting this issue because I had specified my YAML as per @Claudia's answer, but I had specified rmarkdown
as the VignetteBuilder in the DESCRIPTION file. Using VignetteBuilder: knitr
in my DESCRIPTION file fixed the problem.