I think I found the answers for both questions
if it stalls again, I will start a new thread
All the best

Thanks Prof
My bad for the thread, I didn't want to flood with many threads, will keep in my mind
two questions:
how we can make the birth behaves the same, instead of just popping out, I want to animate the radius progressively until it reaches the radius value
how to tell mograph to copy the radius to the scale of the clones ? I saw you created one but in the scene it stays constant
Best

I forgot to add that also the appearance of the particles should be progressive, let's say birth / death around 3-4 frames progression before reaching the radius

Hello
I know it is a simple question, but how we can map the radius of the particles so it is getting smaller before the end of its life, I found the "Radius Over Age" scene in the Asset browser but cannot apply it to my emitter scene

Hello
When a viewport that contains an animated video is deselected "camera view", scrubbing time in another viewport don't update the video frames in the camera view, the viewport that contains the camera view to the animated sequence must be selected.
Is there a way to lock the viewport that contains the video file so working on different viewport can let the video in the locked frame refreshing

submitted as a bug

I noticed also the following,
-putting the mograph in Multi Instance with motion blur renders black frames, back to normal instance object and motion blur works
-in AOV with activating motion blur pass (with or without) motion blur activated renders black frames
At least this happens in my scene, maybe I am not aware of the motion blur limitations with particles or mograph based objects
Cheers

Hello
Once the mograph is deactivated the caching runs without no issue, upon finishing, I activated it all works normally, it didn't matter after if it is normal instances or multi instance
Thanks for being supportive
Best

Good morning Dr.
I made more debugging based on your recommendations
It seems that only the Mograph object being active is causing the crash, all the other elements: cache scene Vs object, baking geos were not the cause of the crash
I will keep digging
cheers

It seems it is getting me the caching issue using the new particles system, long story short, I am trying caching the scene here, bit it keeps crashing or freezing
I tried to debug it by recreating it, I think the moment where I ask for negative time values to get my preroll right this is where things get to be messed up
I am attaching the scene, but no need if I can find a proper and clean way to get like pre-roll of certain number of frames with caching
many thanks

https://we.tl/t-0lm0HGQ7Ep