Dear all, I have a problem to execute Pymol that it is without external GUI and just only the Viewer window. This is the error message I got after executing the pymol. Traceback (most recent call last): File "/home/mauricetam/software/cctbx/cctbx_plus_build/base/lib/python2.7/site-packages/pymol/__init__.py", line 401, in launch_gui __import__(self.invocation.options.gui) File "/home/mauricetam/software/cctbx/cctbx_plus_build/base/lib/python2.7/site-packages/pmg_tk/__init__.py", line 22, in <module> from PMGApp import * File "/home/mauricetam/software/cctbx/cctbx_plus_build/base/lib/python2.7/site-packages/pmg_tk/PMGApp.py", line 28, in <module> from Tkinter import * File "/home/mauricetam/software/cctbx/cctbx_plus_build/base/lib/python2.7/lib-tk/Tkinter.py", line 39, in <module> import _tkinter # If this fails your Python may not be configured for Tk ImportError: No module named _tkinter Thanks for the help. Regards HK