Today’s nightly windows Slicer starts, but all scripted modules are broken. Today’s nightly on mac works fine for me, as does 4.8.1 on the same windows machine.
The first error message is:
>>> import vtk
Traceback (most recent call last):
File "<console>", line 1, in <module>
ImportError: No module named vtk
probably a vtk9 packaging issue.