R: package vignette not built

Problem

I created a small internal package for my company. To describe hot to use it, I wrote a vignette. But for some reason, the vignette is not built when I hit Install and Restart in RStudio.

Further Information

• I use roxygen for the package documentation

• Interestingly, the output from Install and Restart says that it is installed:

  ==> devtools::document(roclets=c('rd', 'collate', 'namespace'))
  
  Updating DataReportR documentation
  Loading DataReportR
  Documentation completed
  
  ==> Rcmd.exe INSTALL --no-multiarch --with-keep.source DataReportR
  
  * installing to library 'C:/Program Files/R/library'
  * installing *source* package 'DataReportR' ...
  ** R
  ** preparing package for lazy loading
  ** help
  *** installing help indices
  ** building package indices
  ** installing vignettes
  ** testing if installed package can be loaded
  * DONE (DataReportR)
  

• devtools::build_vignettes() returns NULL even though the lines

  Suggests: knitr, rmarkdown
  VignetteBuilder: knitr
  

  are included in the DESCRIPTION.

• The YAML header of the vignette looks like this:

  ---
  title: "My title"
  output: rmarkdown::html_vignette
  vignette: >
    %\VignetteIndexEntry{Generate LaTeX tables for Data Reports}
    %\VignetteEngine{rmarkdown::render}
    %\usepackage[utf8]{inputenc}
  ---
  

• I also tried to force building the vignette by devtools::build(vignettes = TRUE) but nothing changed.

EDIT (changed YAML header):

When I change %\VignetteEngine{rmarkdown::render} to %\VignetteEngine{knitr::rmarkdown} in the vignette's YAML header, devtools::build_vignettes() works and places the built vignette in /inst/doc/.

However, when I Check the package in RStudio, the check fails at this position:

** installing vignettes
** testing if installed package can be loaded
Error in namespaceExport(ns, exports) : 
  undefined exports: create_var_details, create_var_overview
Error: loading failed
Execution halted
ERROR: loading failed

Both create_var_details and create_var_overview are exported functions. Here an example:

... 
#' @export
#' 
    create_var_details <- function(...
...

With the old header, the checks were fine.

I figured out that R did not find pandoc. Thus, I added the pandoc path to the PATH environment variable. I also changed the vignette enginge to %\VignetteEngine{knitr::rmarkdown} as suggested in the comments by @R18.

Now the vignette is properly built when I click on Install and Restart in RStudio.

However, checking the package still does not work. See my EDIT to the question. But this in another question: R package: Adding a vignette causes 'undefined exports'