Dear all, I am trying to model a high rise 25 floor courthouse building with multiple shells (12) and many zones (near 500). I have used floor multipliers where I could to make the model simpler but it ended up with 60,000 lines and about 7500 components. The .bdl file doesn't show any error and I have also run a default simulation, which took its time but gave results without any errors. Now in the detailed interface, equest freezes whenever I try to make changes on anything or create a new schedule. Also when I go to the building shell spreadsheet, it shows this "Spreadsheet refresh error" with the following text "Selection list exceeds maximum length of 65,500 characters (98,339required). Notify program support representative". Does it mean that I need to reduce number of spaces/zones or divide my building into two separate files? Any idea how to solve this problem? Thanks, Jude.