Install units package on MacOSX
In terminal: brew install udunits or brew reinstall udunits cd /opt/homebrew/Cellar/udunits/ ls You will see something like: 2.2.28 Then, in R: install.packages("units", configure.args = c("--with-udunits2-include=/opt/homebrew/Cellar/udunits/2.2.28/include", "--with-udunits2-lib=/opt/homebrew/Cellar/udunits/2.2.28/lib"), type="source") And it works !