When you try to modify/define a seismic action, you get the error:
This error is caused by a corrupt definition of the seismic action.
- Try to remove the seismic load group from the model. Close the model. Reopen the model and define the seismic load again.
- If that doesn’t help: close the model. Create an empty Diamonds-project. Import your model using the menu File > Import > Import Diamonds.