Hello, Actively select "Semi-rigid diaphragm" and "Superstructure interactive solution" options to get the most accurate results with the project you sent. In order to shorten the analysis time, I changed the slab finite element widths to 50 cm. There are no errors in the attached project. In the initial version of your project that you sent, there were only shortages of equipment. You got this error because the column reinforcements are locked. You have disabled the "Take wall loads defined on beams" option in the project settings. For this reason, in 7 versions, the wall was solved without load. In version 8, these options have been removed. In 8 versions, if walls are drawn in the model, automatic load calculation is made from the wall objects. If there is no wall in the model, the wall load in the beam settings is taken into account. Check out the attached project. I recommend that you also consider Erhan Bey's warnings. Due to the geometry of your project, it would be appropriate to add dilatation and curtain.