How can I suppress Open File prompt when copying over formula referencing closed workbooks

I have an Excel file that contains formulas that reference external workbooks on a shared network. Each month, I copy the column of formulas over to the next month's column. Then, to update the file path, I highlight the new column and do a Find-and-Replace, swapping the previous month's name for the current month. This practice works fine. The only thing is ... the "Open File" promptbox appears for each formula where I updated the file path (i.e. and this can be hundreds instances!). I wind-up having to choose the file from the exact same file path. It is an unnecessary, and annoying extra step to take. What is the workaround that I'm missing? I prefer an easy shortcut, but I am familiar with macros, so if this is the only way, then I can handle it.

Thanks, Paul, for your response, but I already have it on manual calculate. Still, whenever the formula in each cell tries to pull the value from an external workbook, the file prompt opens even though I already have the correct file path in the formula. If this only happened once or twice it wouldn't be big deal, but I copy these formulas over for each month, and their must be at least 100 instances each month.