HI, 

I just started to learn risks method of ABAQUS. 

When I try to reproduce the example provided in Abaqus example problem guide 1.2.1 snap-through buckling analysis of circular arches. I have got a problem. 

Using the input file (snapbuckling_shallow_step1.inp), the model run successfully. But I can not run the model (snapbuckling_shallow_unload.inp). I checked the help document, but there is no specific descriptions of restarting a model with Riks step. 

Is there any one can help ?

Many thanks

regards