Dear all, I use Ess 13.09, and emacs 23.1, R version 3.02 on Archlinux. Following the example in the R-ArchWiki ( https://wiki.archlinux.org/index.php/R#R_ENVIRON) I specified several options in my Rprofile.R. In particular the prompt specification: options(prompt = paste(paste (Sys.info () [c ("user", "nodename")], collapse = "@"),"[R] ")) # customize your R prompt with username and hostname in this format: *user@hostname [R]* It turns that this line causes strange behaviour of Ess (no warnings or messages when you run R in a shell though). For example, running M-x R, launches R but does not give you the prompt, you have to stop it con C-g and switch buffer to *R*. If you try to knit a document using M-n s, you get the error Unable to find function ".ess_weave", but if you call the knit function on the same document from with the R prompt, it works without problem... Moreover the ess-auto-complete feature simply does not work neither in ESS .mode buffers or IESS buffers (the auto-complete feature works though, completing from words in the buffer o filenames for example) I finally discovered that removing the options(prompt=...) or setting it to a simple string like e.g options(prompt="R>> ") removed all these problems! Strange, isn'it? You can imagine it was a pain to identify the cause of the problem, so I thought It may be useful to others if I post it here! All the best, Mathieu -- Mathieu Kessler Departamento de Matemática Aplicada y Estadística Universidad Politécnica de Cartagena Antiguo Hospital de Marina 30202 Cartagena, España Tef: +34 968338901 Fax +34 968338916 email: mathieu.kessler@upct.es www: www.dmae.upct.es/~mathieu Blog 2013: Año Internacional de la Estadística. [[alternative HTML version deleted]]