I can not choose large deflection option, it is greyed out.

[jdyer]

I am using Creo Simulate Release 4.0 and DatecodeM070

The Large deflection option is unavailable to select for a single pass contact analysis#, do I need a different licences to select this option?

Here are the errors that I faced
*** Warning: Large deformation and/or strain detected during contact analysis.
   More accurate results may be obtained if 'Calculate Large Deformations' is selected.

[SweetPeasHub · Accepted solution]

You need the advanced simulate license to do non-linear analysis.
There are also restrictions to your model. Help Link 

[skunks]

"*** Warning: Large deformation and/or strain detected during contact analysis.
More accurate results may be obtained if 'Calculate Large Deformations' is selected."

This is not a error!

[jdyer]

I have found the answer, it is because I have fasteners with pretension in my model, that is why the large deflection option has been greyed out.