Error in yaml::yaml.load(..., eval.expr = TRUE) : unused argument (eval.expr = TRUE) Calls: <Anonymous> ... parse_yaml_front_matter -> yaml_load -> <Anonymous> Execution halted

[Tree1]

I am getting this error message on multiple .Rmd files. I have reinstalled RStudio and multiple yaml packages. The yaml packages were from two different sources:

1. Cran
2. viking/r-yaml

[andresrcs]

Have you tried completely removing yaml package (even deleting the library folder) and then reinstalling it? this has worked for me in the past.

Also try restarting your R session before reinstalling the package (Ctrl+Shift+F10)

[cderv]

I think this is similar to a known issue that has been encountered before and answered on this forum.
You need to update yaml, rmarkdown, and knitr package . One of them is too old to work with the other.

It also depends if you have an old version of R. You may need to update R or find the yaml and knir versions that works for your version of R

See this answer

YAML error with Rmd when I tri to knit it

R 3.3.2 is an old version. You may have an old version of yaml eval.expr appeared in 2.1.19 See https://cran.r-project.org/web/packages/yaml/ChangeLog You must have a version of yaml that correspond to the one that knitr needs. knitr 1.21 needs yaml >= 2.1.19 (see cran page) Can you check the version of your ? Can you upgrade all your components ? You'll need to get the correct version otherwise. The CRAN time machine for MRAN could help get the at the date of 3.3.2

and See similar issues:
https://forum.posit.co/search?q=yaml%20eval.expr%20%3D%20TRUE