This bug (Krita not starting, crash) happens every time starting after having installed QGIS 3.0.1 on a Win 10 creators update system. Before it all worked fine. It does not occur on Mac system OSX 10.11.6 with the installation of both Krita 4.0.0 and QGIS 3.0.1.. QGIS is a phyton based georaphical Information System (QGIS.org) with a lot of phyton-plugins. 
After having startet Krita 4.0.0 it is loading until the splash window shows "Loading Main Window“. Then ist stops, the Script error (see below) is shown and windows says, that the program does not react any longer. Reinstalling Krita 4.0.0 is not successful. 


IndexError Python 3.6.2: python Thu Apr 19 15:26:24 2018  A problem occurred in a Python script. Here is the sequence of function calls leading up to the error, in the order they occurred. 

 C:\Program Files\Krita (x64)\lib\krita-python-libs\krita\dockwidgetfactory.py in createDockWidget(self=<krita.dockwidgetfactory.DockWidgetFactory object>) 10 super().__init__(_id, _dockPosition) 11 self.klass = _klass 12  13 def createDockWidget(self): 14 return self.klass() self = <krita.dockwidgetfactory.DockWidgetFactory object> self.klass = <class 'palette_docker.palette_docker.Palette_Docker'>  C:\Program Files\Krita (x64)\share\krita\pykrita\palette_docker\palette_docker.py in __init__(self=<palette_docker.palette_docker.Palette_Docker object>) 48 self.cmb_palettes.model().sort(0) 49  50 self.currentPalette = Palette(allPalettes[list(allPalettes.keys())[0]]) 51 self.cmb_palettes.currentTextChanged.connect(self.slot_paletteChanged) 52 layout.addWidget(self.cmb_palettes) # add combobox to the layout self = <palette_docker.palette_docker.Palette_Docker object> self.currentPalette undefined global Palette = <class 'PyKrita.krita.Palette'> allPalettes = {} builtinlist = <class 'list'> allPalettes.keys = <built-in method keys of dict object> IndexError: list index out of range __cause__ = None __class__ = <class 'IndexError'> __context__ = None __delattr__ = <method-wrapper '__delattr__' of IndexError object> __dict__ = {} __dir__ = <built-in method __dir__ of IndexError object> __doc__ = 'Sequence index out of range.' __eq__ = <method-wrapper '__eq__' of IndexError object> __format__ = <built-in method __format__ of IndexError object> __ge__ = <method-wrapper '__ge__' of IndexError object> __getattribute__ = <method-wrapper '__getattribute__' of IndexError object> __gt__ = <method-wrapper '__gt__' of IndexError object> __hash__ = <method-wrapper '__hash__' of IndexError object> __init__ = <method-wrapper '__init__' of IndexError object> __init_subclass__ = <built-in method __init_subclass__ of type object> __le__ = <method-wrapper '__le__' of IndexError object> __lt__ = <method-wrapper '__lt__' of IndexError object> __ne__ = <method-wrapper '__ne__' of IndexError object> __new__ = <built-in method __new__ of type object> __reduce__ = <built-in method __reduce__ of IndexError object> __reduce_ex__ = <built-in method __reduce_ex__ of IndexError object> __repr__ = <method-wrapper '__repr__' of IndexError object> __setattr__ = <method-wrapper '__setattr__' of IndexError object> __setstate__ = <built-in method __setstate__ of IndexError object> __sizeof__ = <built-in method __sizeof__ of IndexError object> __str__ = <method-wrapper '__str__' of IndexError object> __subclasshook__ = <built-in method __subclasshook__ of type object> __suppress_context__ = False __traceback__ = <traceback object> args = ('list index out of range',) with_traceback = <built-in method with_traceback of IndexError object>  The above is a description of an error in a Python program. Here is the original traceback:  Traceback (most recent call last): File "C:\Program Files\Krita (x64)\lib\krita-python-libs\krita\dockwidgetfactory.py", line 14, in createDockWidget return self.klass() File "C:\Program Files\Krita (x64)\share\krita\pykrita\palette_docker\palette_docker.py", line 50, in __init__ self.currentPalette = Palette(allPalettes[list(allPalettes.keys())[0]]) IndexError: list index out of range