Installing R on Mac – Warning messages: Setting LC_CTYPE failed, using “C”
Open Terminal Write or paste in: defaults write org.R-project.R force.LANG en_US.UTF-8 Close Terminal (including any RStudio window) Start R For someone runs R in a docker environment (under root), try to run R with below command, LC_ALL=C.UTF-8 R # instead of just `R`