EA Motive has run into a crash when using the hair card generator plugin. A missing DLL is preventing them from creating hair cards according to the initial investigation from their engineers. More information can be found in the linked EPS case
LogPython: Display: Running start-up script D:/dev/HopperNewDepot/main/Engine/Plugins/MovieScene/MovieRenderPipeline/Content/Python/init_unreal.py... took 3.568 ms (total: 2.09 sec)
LogPython: Display: Running start-up script D:/dev/HopperNewDepot/main/Engine/Plugins/Importers/USDImporter/Content/Python/init_unreal.py... started...
LogPython: Display: Running start-up script D:/dev/HopperNewDepot/main/Engine/Plugins/Importers/USDImporter/Content/Python/init_unreal.py... took 507 us (total: 2.09 sec)
LogPython: Display: Running start-up script D:/dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python/init_unreal.py... started...
LogPython: Error: Traceback (most recent call last):
LogPython: Error: File "D:/dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python/init_unreal.py", line 15, in <module>
LogPython: Error: from CardUEInterop import instantiate_card_gen_controller
LogPython: Error: File "D:\dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python\CardUEInterop__init.py", line 2, in <module>
LogPython: Error: from .ue_card_gen_controller import HairCardGenController
LogPython: Error: File "D:\dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python\CardUEInterop\ue_card_gen_controller.py", line 10, in <module>
LogPython: Error: from Modules.Geometry.cluster import ClumpGenerator
LogPython: Error: File "D:\dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python\Modules\Geometry__init.py", line 12, in <module>
LogPython: Error: from .optim import GeometryOptimizer
LogPython: Error: File "D:\dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python\Modules\Geometry\optim__init.py", line 12, in <module>
LogPython: Error: from .card_optimizer import CardOptimizer
LogPython: Error: File "D:\dev/HopperNewDepot/main/Engine/Plugins/Experimental/HairCardGenerator/Content/Python\Modules\Geometry\optim\card_optimizer.py", line 18, in <module>
LogPython: Error: import torch
LogPython: Error: File "D:\dev\HopperNewDepot\main\Hopper\Intermediate\PipInstall\Lib\site-packages\torch__init.py", line 148, in <module>
LogPython: Error: raise err
LogPython: Error: OSError: [WinError 126] The specified module could not be found. Error loading "D:\dev\HopperNewDepot\main\Hopper\Intermediate\PipInstall\Lib\site-packages\torch\lib\fbgemm.dll" or one of its dependencies.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-250447 in the post.