I have a workbook with a worksheet for each month of the year. The worksheets are identical apart from their title, which is just the name of the month. There is a thirteenth workbook which is a summary of the year. It contains formulae with references to the month worksheets, simple stuff like 'January!AC23'. Sometimes the design of the month worksheet needs to change. To do this, I delete all months but January, make the required changes to January, then run a macro which creates the other months of the year by copying and renaming January. The problem is that deleting a worksheet causes the #REF! error on the year summary worksheet, and recreating the month worksheets does not get the formulae working again. I know I can get around this by using INDIRECT and storing the names of the months in the summary worksheet, but is there another way?