I'm having a problem installing/running 10.4.1 when after the installation of 10.4.1, the application fails to launch. The opening sequence starts and reaches "Loading Document" and then mysteriously vanishes. I had this same problem when I installed 10.4 on the same machine and our IT group said it had something to do with Python 2.7.11 which was installed on my machine for a Python course (which was confirmed by our PS rep). Once that version of Python was removed, ArcMap opened with no issues. The only version of Python on my machine currently is the version pre-packaged with 10.4.1 which is 2.7.10. Typically I'd just call PS, but since we block any screen sharing outside of our company it's a bit difficult. Anyone experiencing anything similar?