I have one source file that holds all my input costs. I then have 30 to 40 destination files (costing sheets) that use links to data in this source file for their various formulae. I was sure when I started this system that any changes I made to the source file, including the insertion of new rows and columns was updated automatically by the destination files, such that the formula always pulled the correct input costs. Now all of a sudden if my destination files are closed and I change the structure of the source file by adding rows - the destination files go haywire? They pick up changes to their linked cells, but don't pick up changes to the source sheet that have shifted their relative positions in the sheet. Do I really need to open all 40 destination files at the same time I alter the source file structure? Further info: all the destination files are protected, and I am working on DropBox.