what type of study is it? what is in the study?
there are some elements that aren't supported by the ffe solver which automatically forces it to direct sparse.
there are a couple of really good articles about this in the solidworks KB.
if you're stuck with direct sparse because what is in the setup, i'd recommend looking at the setup overall to see how you can simplify it.
It is a static model with contacts.
The model simulates the mechanism of two booms and a frame connected by 4 cylinders. Some of the cylinders and the pins are modeled by using beam and truss. I realize now Solidworks iterative solvers does not support beam and /or truss.
probably just a limitation of the calculation methods. i'd submit a question to your reseller or an enhancement request for the functionality.
in the end, if you have contact, going to direct sparse is better.