Converting linear static cases to nonlinear static when I run calculations

[if.franco1139]

Good evening. I'm modelling a Silo structure. I define my load cases as linear static. When I hit calculations, the program automatically converts them to nonlinear cases, which in turn cause an error during modal analysis. I do not know why this is happening if all the elements I have are Bars. Can someone help me?

[Rafal.Gaweda]

Tensioned only members make model nonlinear so all cases \ combinations become nonlinear automatically.

I do not see any problem to calculate this model.

(BTW you have not corrected model or attached the old one because there are acis panels in it causing mesh incoherence)