Updated to R 4V.0.0 for summer term instructional purposes. Followed all guidance RE installation to use RMD for knitting to HTML, WORD, PDF, as I have done for previous course iterations and version of R and RStudio. But while HTML & WORD knit, PDF will not. Error returned is below. NOTE my 3.5.X and 3.6.X all still work, and I implemented the same installation process for 4.0.0. Unlike other versions, install of tinytex etc does not place a luatex.dll in .\TinyTeX\bin\win32 directories. Curiously, luatex.dll is found in my older 3.5.X and 3.6. Similarly, pdflatex.fmt mising in install from 4.0.0. is current for R4.0.0, with path added per website. In all cases followed advice from Yihui Xie et al. websites.
Have tried several re-installs, including a full install of MikTeX. No joy.
output file: test1.knit.md
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020/W32TeX) (preloaded format=pdflatex)
restricted \write18 enabled.
I can't find the format file `pdflatex.fmt'!
Running the command C:\Users\tce\AppData\Roaming\TinyTeX\bin\win32\fmtutil-user.exe
kpathsea: Running mktexfmt pdflatex.fmt
The command name is C:\Users\tce\AppData\Roaming\TinyTeX\bin\win32\mktexfmt
I was unable to find any missing LaTeX packages from the error log test1.log.
! Running the command C:\Users\tce\AppData\Roaming\TinyTeX\bin\win32\fmtutil-user.exe
! kpathsea: Running mktexfmt pdflatex.fmt
! The command name is C:\Users\tce\AppData\Roaming\TinyTeX\bin\win32\mktexfmt
Error: LaTeX failed to compile test1.tex. See https://yihui.org/tinytex/r/#debugging for debugging tips. See test1.log for more info.