I'm not very experienced with SSR Method, but when I run the program to narrow down a FOS, I sometimes get highly variable values. For example I ran an analysis and Adonis returned a FOS of 0.996 one time then hit run again and Adonis returned a FOS of 1.565. Is this normal using FEM SSR method?

No it is not normal it should give same fos unless there is a bug in the subroutine. Woud yo ou please attach your model’s script so I can check it out?

now I understand, if you use the same solved model and hit "solve fos" you will always get somewhere close to fos=1.0 because the shear strength parameters are already reduced by the factor of 1.545 which was the latest calculated fos and at this point model is at the stage of failure. if you want to run it again you need to re-start your model from beginning.

so I believe program works correctly.