Re: SYSTEM UNABLE TO SOLVE ERROR There are a few bugs in geometry check, fix them. reason for interruption of analysis: Stairs. for solution; 1= Delete the stairs, manually calculate the stair loads and give it as an additional load to the supporting beams, 2= If you are going to make a solution with stairs, connect the stairs to the supporting objects and fulfill the support conditions, use the semi-rigid diaphragm option in the analysis settings. I tried solution 1, analysis is happening. Greetings and love. G.KÖSE