Hi Jeremie, I just tested with Org mode version 9.5.3 (release_9.5.3-504-gcdbb1c @ /home/heinrich/.emacs.d/straight/repos/org/lisp/) using GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.16.0) of 2021- 11-27, modified by Debian I am on Debian Testing and that is the default emacs version. Using the unmodified org (git hash from above) I get the following messages when executing a src block with R: executing R code block... Loading ‘ess-bugs-l’: unescaped character literals `?(', `?)' detected, `?\(', `?\)' expected! Type C-h m for help on ESS version 15.09 ess-tracebug mode enabled Quit Package cl is deprecated Note that the "Quit" is me pressing Ctrl-g after a few seconds. Removing the commit in question makes the block return instantaneously: executing R code block... Loading ‘ess-bugs-l’: unescaped character literals `?(', `?)' detected, `?\(', `?\)' expected! Type C-h m for help on ESS version 15.09 ess-tracebug mode enabled Code block evaluation complete. Package cl is deprecated I anticipated that this would not be obvious, since this feature is used too much to go unnoticed for two years - but I am clueless as to how I should continue with debugging... Thanks for your help! Christian On Sun, 2022-05-15 at 16:16 +0200, Jeremie Juste wrote: > > Hello Christian, > > Thanks for reporting but I cannot reproduce the bug with the org and > emacs version below. > > Org mode version 9.5.3 (release_9.5.3-467-g2bd34e @ > /home/djj/src/org-mode/lisp/) > GNU Emacs 27.2 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24) of > 2022-01-16 > > Can you please let me know which version of org-mode you are actually > using? > > Ihor, many thanks for checking. > > Best regards, > Jeremie > > On Sunday, 15 May 2022 at 16:08, Ihor Radchenko wrote: > > Christian Heinrich writes: > > > > > I got back to an org file after upgrading to the latest release of org-mode and tried > > > executing the > > > contained R source blocks. Unfortunately, emacs got stuck in the execution and was blocked; I > > > had to > > > exit using C-g. > > > > > > Here's a minimal example src block that causes emacs to get stuck: > > > > > > #+begin_src R :results output :session *R* :exports both > > >   a <- 10 > > >   a > > > #+end_src > > > > > > R itself does start and the code is also executed correctly. However, the output from that > > > session > > > is apparently not returned to emacs or the buffer. > > > > I tried you example using Emacs >=26 and it works just fine. > > > > Best, > > Ihor