Thanks for the quick response Karthik. No, I can't open the model in a new instance of WB. I've tried everything I can think of on that front; computer restart, different computer, reinstall WB, duplicate WB project file, etc, etc. The only way that works is if I edit the mesh and rebuild the model from from there. nIt seems to be an issue that WB has with the model. There are a couple of other bits of information that might have a bearing on the problem.nIt is a 16M cell model with 4 partitions.nIt doesn't seem to be running out of memory (I still have 30Gb spare)nThe problem only appears after the model has been run.n