Hi, is there a way to prevent the formulas in a spreadsheet from automatically updating, especially when the file is just opened, unless specifically given the ok?

for example, in workbook1-sheet1, I have formulas referencing cells in another workbook. Every time I open workbook1, all the cells with formulas have a #REF! because I haven't opened the other workbook yet. Is there a way for the workbook to open, but not run the formulas until I say to.

thanks