Locking and Unlocking the Model

Use the  Options menu > Lock Model command or the corresponding toolbar button to lock or unlock the model. This command functions as a toggle, alternately locking and unlocking the model.

Locking the model prevents changes to it. SAP2000 automatically locks the model after running an analysis to prevent any changes that would invalidate the analysis results. When the model is locked, most Edit, Draw, Define and Assign commands that directly affect the objects are not available. One exception is the Define menu > Load Cases commands, which can be used to define or modify a load  case when the model is locked. If the definition of a load case that has already been run is changed, SAP2000 will display a warning that the analysis results will be deleted for that case and for all cases that depend on it.

Design operations can be performed on a locked model — in fact, they must be performed on a locked model because the analysis results must be present.

Commands that affect groups, views, and display items are not locked.

When a model for which analysis results are available is unlocked, SAP2000 will display a warning that unlocking the model will cause all analysis results to be deleted.