System Information
OS: Windows 10 build 15063.540
CPU: Intel i7 6700K
GPU: Nvidia GTX 1070

Blender Version
Broken: 2.79.0 0bbae3f
Worked: 2.79.0 4f1b510

Short description of error
Cycles are not enabled after starting the new blender build the first time. It will not enable in the user preferences.

Exact steps for others to reproduce the error
Deleted the 2.79 folder at

%appdata%\Blender Foundation\Blender\2.79

Downloaded the new blender build.
Opened blender from the unzipped folder
Cycles don't show in the engine drop down. In the add-on tab in user preferences cycles is enabled.
Disable and enable it.
And this I get this error

Traceback (most recent call last):
  File "E:\johan\Documents\Blender\blender-2.79.0-git.0bbae3f-windows64\2.79\scripts\modules\addon_utils.py", line 350, in enable
    mod.register()
  File "E:\johan\Documents\Blender\blender-2.79.0-git.0bbae3f-windows64\2.79\scripts\addons\cycles\__init__.py", line 131, in register
    properties.register()
  File "E:\johan\Documents\Blender\blender-2.79.0-git.0bbae3f-windows64\2.79\scripts\addons\cycles\properties.py", line 1419, in register
    bpy.utils.register_class(CyclesRenderSettings)
ValueError: register_class(...): already registered as a subclass

When I opened blender the first time where was also a lot of errors in the terminal.
It is the same on an other Windows 10 pc.