Dear Christophe: It seems to me that the problem is at launching Gmsh in the command line with the -listen option: /Applications/Gmsh.app/Contents/MacOS/Gmsh -listen & The menu bar does not appear and the socket does not work. When Gmsh starts clicking the app icon and then setting always listen option then it works fine. This problem is new in 2.4.* versions. Thanks in advance. Jose M. Sancho