I've had experience with this issue. Load a new project, set iclone to minimal mode, load your project, enable one shader at a time in preferences, save and reopen the project, then enable another, save and reload. This process may help determine  what shader in particular might be at fault.  I'm certain it would be in smoothness/subdivision and displacement, or physics which currently has a bug/ technological limitation of the hair with physics and soft cloth/ physics applied to clothing or the character's  skin with cloth vs cloth physics enabled in project settings. The final possibility might be a memory issue. Upgrading iClone may have required iclone to use more memory for features like crowd simulation and scatter tool, you may have simply made your project too large for your current installed ram.  You could try to increase your windows virtual memory size to 32 gb, then load your project.   I'm  not reallusion's staff, but I've had years of experience with Reallusion software and have helped others bypass limitations of the software.  I've been requesting that Reallusion add occlusion +frustum culling system that could easily prevent iClone crashing due to low resources and a feature in preferences that teaches/ tells users to set their virtual memory and windows system priority of iClone exe higher which is located in the details area of the task manager (alt+control+delete)  I hope that helps.