Our most recent release of Mantid, v3.9.1, contained a couple of issues primarily for Muon instruments that had not been highlighted in time for the fixes to be incorporated into v3.9.1. We have put together a patch release to address these issues and we are pleased to announce that this is now available.
Installation packages can be found at http://download.mantidproject.org and the details of what is contained in the patch can be found at http://docs.mantidproject.org/v3.9.2/release/v3.9.2/index.html