As requested by José, I installed Python 3.6.1 and tested today's master
with it. As result LyX cannot be started because the reconfiguration fails:
02:05:53.187: Checking whether TeX allows spaces in file names... yes
02:05:53.188: Traceback (most recent call last):
02:05:53.189: File "D:/LyXGit/Master/lib/configure.py", line 1814, in
<module>
02:05:53.192: windows_style_tex_paths = checkTeXPaths()
02:05:53.193: File "D:/LyXGit/Master/lib/configure.py", line 206, in
checkTeXPaths
02:05:53.194: inpname = shortPath(str(tmpfname,
encoding)).replace('\\', '/')
02:05:53.196: TypeError: decoding str is not supported
02:05:53.198: configuration will be reloaded...
D:\LyXGit\Master\src\support\Systemcall.cpp (295): Systemcall: 'python
-tt "D:/LyXGit/Master/lib/configure.py"
--binary-dir="D:/LyXGit/Master/compile-2015/bin/Release/"' finished with
exit code 1
regards Uwe