Good morning everyone,

I am using CST Studio Suite  2024 Learning Edition and I am encountering a recurring and blocking issue.

When I build a design and run the initial simulation, everything works perfectly. However, if I try to change the mesh values in the Global Mesh Properties (while ensuring I stay well below the 100,000 cells limit of the Learning Edition) or if I set up a Parameter Sweep, the simulation is interrupted and returns the following error in the Messages window:

"Error in calculating solver matrix"

I have noticed a specific pattern: normally, the simulation tasks take very little time. But when this error is about to trigger, the software hangs for a long time at the step "Calculating matrices: Finished CAD processing" before eventually throwing the error.

The major problem: Once this error occurs, the .cst file seems to be permanently corrupted. Even if I revert the Global Mesh Properties back to their default values and completely delete the Parameter Sweep sequences, every subsequent simulation attempt on that file results in the exact same error.

The software acts as if the file is marked for life, and the only workaround I have found is to completely delete the .cst file and its associated result folders, and rebuild the entire project from scratch.

Could you please help me understand what is causing this solver matrix error and how I can recover my simulation files without having to start over every time?

Thank you in advance for your support!