I sometimes uploading an pvz doesn't work. CAD-Optimizer goes through till low level, then runs endless. In the error log you can see the error "debug: [twx-studio:cad-import-filters] Program exit code 0".
There is a workaround:
Go to C:\Users\***\AppData\Local\Temp\
Here yo find a folder named Studio-optimize... with some digits behind
Go into that folder, copy the file with the wanted resultion and paste it into your project path,
I do not think that this could be answered in generally without the model. Currently there is only one issue known (reported in 8.4.5 and in the means team it should be already fixed and will be provided with the next releases / pvaroptimizer Fatal: Received signal 11, terminating/ but it seems not to be the same as your problem. May be, you can check more detailed the model where the problem occurs / e.g. you can open it in Creo View and edit the structure /advance/ and remove components to see if this could change the behavior/ Another question is the problem based on an assembly or is in this case based on component What is specific on this model /texture or some geometry interference or geometry errors… You can try to remove a specific component or replace it… Other thing is to check if the issue occurs with the original format / for example on the model exported directly from Creo Parametric or the issue occurs after it was published by Creo Illustrate. So, when you have an issue which is always reproducible with a specific model, maybe you can share the model with PTC so we can report it with the development team