#BUSY tells the user that Excel is currently recalculating the spreadsheet. Recalculation times are a function of spreadsheet complexity, the amount of =SCOTT functions used in the sheet, and Internet bandwidth. The functions that work the hardest, and take the most time to process, are RANGE functions.  Please use these judiciously. Another possible cause of #BUSY is a Microsoft 365 update.  Please try re-installing the add-in.