After updated to macOS Catalina (10.15) I've been trying to use R in Emacs 26.3. However, Emacs is not fetching R by using M-x R (Emacs says [No match]).

I already checked the paths for both R and Emacs in the Terminal, both are in /usr/local/bin. Also, I checked M-x getenv PATH within Emacs. This is the result:


Can anyone help me with this please? Any ideas to fix the problem? Please let me know if you need more info.

  • Apparently there is no Emacs command named R in your setup.
    – Drew
    Oct 18, 2019 at 17:53
  • Have you (re-)installed ess? You need that to run R.
    – Tyler
    Oct 18, 2019 at 18:07
  • 1
    The command R disappeared somewhere between version 16 and 18 of ESS. See #787 of the ESS git repository on github. Solutions are discussed there. You can define your own alias but you must wait for the detection of the newest R version. The problem should be solved in the newest version of ESS directly from github since the ticket is closed with a commit. R-newest should be some replacement for R (see the comment of jabraham).
    – Tobias
    Oct 18, 2019 at 20:57
  • 1
    @Tobias the problem you link to was fixed in April; the version of ESS in Melpa includes the fix. So just reinstalling ESS from Melpa should fix the problem.
    – Tyler
    Oct 18, 2019 at 22:01
  • @Tyler - Thank you very much for your help. I re-installed ESS and R came back in Emacs. @Drew and @Tobias, thanks for your comments and for editing my question, I appreciate you!
    – Dylan
    Oct 19, 2019 at 2:03

1 Answer 1


The command M-x R is provided by the package ESS, which is available via the Melpa repository. You need to install this package before you can start the R process this way.

There was a period in early 2019 when the R command was broken in ESS, but it has since been fixed, so installing the current release of ESS should restore the R command.

  • Confirming this works on Big Sur after installing macOS R app from official source.
    – Paul
    Apr 23, 2021 at 20:01

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