Installing R on Mac - Warning messages: Setting LC_CTYPE failed, using "C"

  1. Open Terminal
  2. Write or paste in: defaults write org.R-project.R force.LANG en_US.UTF-8
  3. Close Terminal (including any RStudio window)
  4. 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`

Setting locales in terminal resolved the issue for me. Open the terminal and

  1. Check if locale settings are missing

    > locale
    LANG=
    LC_COLLATE="C"
    LC_CTYPE="UTF-8"
    LC_MESSAGES="C"
    LC_MONETARY="C"
    LC_NUMERIC="C"
    LC_TIME="C"
    LC_ALL=
    
  2. Edit ~/.profile or ~/.bashrc

    export LANG=en_US.UTF-8
    export LC_ALL=en_US.UTF-8
    
  3. Run . ~/.profile or . ~/.bashrc to read from the file.

  4. Open a new terminal window and check that the locales are properly set

    > locale
    LANG="en_US.UTF-8"
    LC_COLLATE="en_US.UTF-8"
    LC_CTYPE="en_US.UTF-8"
    LC_MESSAGES="en_US.UTF-8"
    LC_MONETARY="en_US.UTF-8"
    LC_NUMERIC="en_US.UTF-8"
    LC_TIME="en_US.UTF-8"
    LC_ALL="en_US.UTF-8"