There is not sufficient information in the images you sent, which is why it is always better to attach the setup files. If you have proprietary geometry, you can prepare a different setup that still reproduces your issue. Otherwise we can only guess and/or ask you additional details.
Do you have particles initially in the system? If you don’t, the vtp files will not be written until there is at least one particle in the vtk region.
Is this a granular flow (no fluid phase)? The time step you want to set is the fluid time step. It is not recommended to use a constant fluid time step because the simulation will stop if any fluid loop fails to converge or if unphysical values are computed, instead of reducing the time step and continuing the simulation.
If you want a constant solids time step, then set the solids time step option to “constant” and enter the solids time step (see below). However, DEM is unlikely to run with such large time step, given that the computed DEM time step is 3 orders of magnitude smaller.
