In STAAD.Pro, go to . In the save options, look for “Save as type” and choose “STAAD Input File (Text) (*.std)” rather than the default binary database format. Text files are human-readable and much easier to repair.
STAAD cannot read curly quotes. If you have a load case title like LOAD 1 "Dead Load" , ensure those are straight quotes. Retype them manually in the editor. This Is Not A Valid Staad Command File