Hi @BimPaul ,
thank you for the CER number.
Unfortunately, there is not much useful information in the CER report that helps for troubleshooting.
What I can say is that the program crashes in a module that creates the terrain surface. So, I assume there is a problem merging terrain data sets or calculating road grading, tunnel, etc.
Without taking a look at the model directly, I cannot say more.
It might help to "repair" the model with the tool mentioned in https://forums.autodesk.com/t5/infraworks-forum/model-recovery-tool-available-for-beta-testing/td-p/...
Regards,
Karsten.
Karsten Saenger