I think I'm having the same issue.

0.001 2016-06-27 14:54:45; Factorio 0.13.0 (Build 22782, win64, alpha)
0.001 Operating system: Windows 10
0.001 Not rotating logs.
0.001 Program arguments: "Z:\Factorio_0.13.0\bin\x64\Factorio.exe"
0.001 Read data path: Z:/Factorio_0.13.0/data
0.001 Write ...