Thank you for your quick reply.

I will check with our IT department if Ansys Rocky is available for me. If so this might be a better solution.

We are using DEM to get a more detailed picture of the bed and would prefer to stick with it, if it is possible to get it to run.

Currently I am not using hi-res tracking. I did some tests with it and found that convergence is even worse with hi-res turned on.