data.table - No RTools compatible with R version 3.5.0 was found

Question

I had problems installing data.table for R version 3.5.0, and was advised to check that RTools was properly installed.

After installing RTools 3.5 (this seems to be the latest) I typed

find_rtools(T)

I got the following message:

WARNING: Rtools is required to build R packages, but no version 
of Rtools compatible with R 3.5.0 was found. 
(Only the following incompatible version(s) of Rtools were found:3.4,3.5)

Please download and install the appropriate version of Rtools from 
http://cran.r-project.org/bin/windows/Rtools/.

So on the one hand it looks like I do have 3.5 installed, but it seems to think there is a newer/different version.

Any thoughts?

Answer 1

The problem was Rtools 3.5 was not in your Windows system PATH thus find_rtools couldn't find it. Another possibility was that an incompatible version of Rtools was in the PATH

Best practice for installing Rtools:

• Download the latest version

• Install RTools at default recommended location (at the root of your C drive): C:/Rtools/

• <Important> Check the box that allows Rtools to modify system PATH

After the installation, we can double check by running this command inside R

R> Sys.getenv('PATH')
[1] "C:\Program Files\R\R-3.5.0\bin\x64;c:\Rtools\bin;c:\Rtools\mingw_64\bin;

See also this guide

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Edit: for those who don't have Administration rights, see these links:

• Rtools with R portable
• Building R packages on Windows without administrator access
• Setting up RStudio Portable Default R version