LightBuilding from commandline in UE4.15 always fails.

Hello,

I’m trying to light build a scene from commandline in Unreal 4.15.3 using the following command:

“D:\Program Files\Epic Games\UE_4.15\Engine\Binaries\Win64\UE4Editor-cmd.exe” “D:\Unreal Projects\LightBakeTest415\LightBakeTest415.uproject” -run=resavepackages -buildlighting -AllowCommandletRendering -MAP=Minimal_Default

The error it gives me (see log) :
Assertion failed: RenderTarget [File:D:\Build++UE4+Release-4.15+Compile\Sync\Engine\Source\Runtime\Engine\Private\UserInterface\Canvas.cpp] [Line: 260]

Does anyone have an idea of what I’m doing wrong?

Thanks in advance!