I have an SSRS 2005 report that appears normal in SSRS; however, a duplicate set of rows is added below the second row grouping when exported to Excel 2007.
I am not all that familiar with the more advanced reporting techniques in SSRS 2005, and am struggling to find the right answer. Is there any way to remove this?

(Original image here: https://i.stack.imgur.com/sCchD.jpg)
It looks as though your report matrix is grouped by Year, Staff Category, Name and Office. If there is never more than one Office per Name, then the solution is:
=Fields!Office.Value. (Don’t drag and drop the column from the dataset, or you may inadvertently add a grouping on Office to the matrix.)