This type of problem can be random and hard to reproduce. There are 2 possible reasons: 1. RAM limitation. Check solve.out file and see if you have following message “Pivoting has been activated for the Distributed Sparse Matrix Solver. The memory required may greatly exceed the predicted amount.” If yes, try to run the model on a machine with larger RAM. 2. There is a third party security software on your system that is causing some of the ANSYS files to be unavailable. Check with your IT about possible third party software conflicts.