This could mean you have an emacs that was not compiled with libxml. Type C-h v system-configuration-options and look for --with-xml2 to see if your emacs was built with it. John ----------------------------------- Professor John Kitchin (he/him/his) Doherty Hall A207F Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213 412-268-7803 @johnkitchin http://kitchingroup.cheme.cmu.edu On Mon, Oct 18, 2021 at 4:12 AM Timothy wrote: > Hi Joseph, > > The function libxml-parse-xml-region has been around for a while, what > version > of Emacs are you running? > > All the best, > Timothy >