Convergence Failed with UpdateMaterial

[dks]

I did a analysis with gravity loads and surface loads in 2 stages for a PIMY soil. But when I'm trying to update material property after gravity analysis like changing Br and Gr, I'm unable to achieve convergence.
This is not happening when I don't update material properties, keeping rest things exactly same.
Why is it happening? Please suggest some ways to analyse this.

thanks

[dks]

I tried with umfpack for surface load analysis after updating material properties. It is analysing but displaying a warning at each analysis step that lvalue is too small. The results are also not correct. May be it is not updating material at all and even not doing the analysis for surface loads and results are same as gravity load analysis. Please someone suggest how to deal with it?

Thanks