Some packages in Windows require an additional tool to be installed, the tool is called… …’R Tools’.

When do you need R Tools?
R Tools is often needed when you install a package that is older than the version of R you are using.

When you use groundhog.library(pkg,date) you will get a warning if you enter a date that does not match the version of R you are using.
For example, if you use R-4.0, released in 2020, to load the package dplyras available in 2017:

groundhog will recommend you switch to an older R version, or that you use a more recent date:

But if you type “OK” , groundhog will proceed, and at that point, you very likely will need R Tools.

You could need R Tools even if you are using the matching version of R, but less often.

You can obtain R Tools and learn more here

Below we try to provide more basic information:

Two key facts about R Tools

  1. You need different versions of R Tools for different versions of R
    • For R > 4.0.0 you need R Tools 4.0 (.exe)
    • For R-3.3 till R-3.5 you need R Tools 3.5 (.exe)
    • For R-3.1 till R3.2 you need R Tools 3.2 (.exe)
  2. R needs to somehow know that R Tools is installed. Sometimes this happens automatically, sometimes it is does not.
    If in R you run Sys.which("make") and get nothing back, “”, R does not know where R Tools is. If you get something like “C:\\Rtools\\bin\\make.exe” , it does.
    If you you have R Tools but R does not know it, start your search for a solution here:

The ultimate test that R Tools is properly configured is to be able to install packages with it. This is one test the R Tools page recommends:

If it installs, R Tools is working for you.

Last updated: 2021 01 06