Load props with Substance, check and uncheck the Activate checkbox in Substance section, and use Undo/Redo cause possible crash
STEPS TO REPRODUCE 1. Launch iClone 6 2. Navigate to Content Manager > Set > Props > 3D Blocks > Arc, apply a random prop (e.g. Arc_001) 3. Go to Modify > Material > Substance, load a .sbsar file, then uncheck the box for "Activate" 4. Save it to Content Manager > Set > Custom > Props 5. Click "New Project" on Toolbar, and then, apply this prop again 6. Go to Modify > Material > Substance, check the box for "Activate", then uncheck it 7. Click "Undo" on Toolbar, then click "Redo" 8. Go to Modify > Material > Substance, check the box for "Activate"
