An updated version of this post has been published here:
Have you ever deleted something from an Excel Workbook, only to discover that all your formulas suddenly return #REF or #VALUE, or something else you didn’t expect? There is an easy way to avoid that. Before you delete a cell, always check first if there are other cells affected by it. Here’s how to do it:
Select the cell, go to the Formulas ribbon and click on Trace Dependents. The arrows show the dependent cells.