Hello AKnauerMaxon,
Did you receive my two files via Maxon ticket ?
Yes, we received the bug report. Thank you for submitting! We are working on a fix, but I couldn’t tell you right now, how long it will take.
Thank you !
This issue is really impacting our project in a bad way. Could it be at least possible to know if we are speaking of days, weeks, or months before having a fix ?
Thank you
I have a fix already. I could provide you with it at the end of the week.
The problem is, that once you get the fixed plugin, you will have to apply your materials, positions and other overrides again but only once. Then, all other future re-imports should work.
I’m very sorry for your inconvenience. The re-import functionality was just never implemented.
Copying this message for @LoicDerrien. It seems the posting time limits are really getting in the way here.
Hello @UE_FlavienP . I’m waiting for a fix from Maxon to my reimport problem. But digging a bit we found this :
Double clicking on the Datasmith uasset shows an empty window, no geometry list, nothing. And that is the case for all my Datasmith uasset in the scene. That is probably why a loose all the overide (at best) or brake all the object (at worth) when I reimport. maxon says it’s an Unreal problem.
This is completely awkward. Just until a week ago I’ve been using C4D 25.117 and UE 5.0.3 with datasmith without any issues at all importing, re-importing, materials worked, geometry worked, imported really fast even with complex geometry. However this morning when trying to re-import an object suddenly it didn’t worked. The same crash everybody is having, but mine stops at 1% when importing. Now the odd thing is I haven’t updated anything for the last month, no C4D updates, no files updates for the last week, no UE5 updates, not even Datasmith updates. So I tried a new UE5 blank scene project importing the same object:crash; a new UE5 blank scene with a basic C4D cube: crash.
Datasmith definitely stop working for no reason, despite I haven’t update anything since a month, and it was working smoothly until today , that’s why I’ve found this opened thread about it. It completely messed up with the project I was working on and had a preview for today. 
Hello Flavien,
Did you see the post above posted for me by Tyler? I think this could be related to the problem.
I would also insist on the fact that limiting my number of post doesn’t really help, even if those are forum rules (maybe a bit exaggerated)
We are struggling with this issue as it is blocking us.
Hello,
Could you double click on the Datasmith uasset (Datasmith scene) of your scene in UE and tell me if the window that pops
up is empty or not ? Mine are totally empty, nothing in it and it’s not normal at all.
That is where you should go.
I can’t even locate the Datasmith Uasset folder inside my project, doesn’t exist at all
The problem of the empty window is solved, for some reason I ignore, everything was hidden and I had to activate it.
Hello Flavien,
After a long worrying time for our project we came to a very simple solution, proposed by AKnauerMaxon. Before importing or reimporting I just rename my Maxon Cinema 4D R25B folder as whatever I want and then proceed, without Cineware of course, only Datasmith.
It works perfectly, import and reimport, with all the overrides, as it always did before 5.0.3.
So we highly recommend you to not discard Datasmith and keep it as it is. We won’t use Cineware anymore, even updated, as our project would be heavily compromised in the middle of its devlopment.
We really hope you’ll take this into consideration for any future update.
hey there, Is the C4D to Unreal still crashing for you all? I have project built and animated in C4D and I would love to light and render out in UE, but it seems to be crashing inconsistently for me. Even when I change the name of the C4D file .
Using UE5.03 and C4D R25. 1.2.1
For me it crashes just after import.
Found this solution that works for me here: