Troubleshooting suggestions, organized in order of complexity, and listed as follows:

• Release only one end. Ensure that releases are not assigned to both ends of frame objects. Releasing both ends may keep load from being able to transfer, leading to numerical problems. Information on numerical problems is available using the Standard Solver, available through Analyze > Set Analysis Options > Solver Options. Check for instability warnings in the log file by selecting File > Show Input Log Files.

• Avoid full fixity and full rigidity. Rather than applying full fixity to DOF, and full rigidity to structural objects, restrained and rigid conditions should be modeled using sufficiently large stiffness values, perhaps on the order of 1e11. Stiffness values may be assigned using spring constants, property modifiers, or section properties. Full fixity or full rigidity may cause numerical sensitivity in linear solutions, and singularities in nonlinear numerical formulation, leading to convergence problems or instabilities.