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 at 17:53
  • Have you (re-)installed ess? You need that to run R. – Tyler Oct 18 at 18:07
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    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 at 20:57
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    @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 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 at 2:03

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.

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