"Reference isn't valid"
A click on a link, a drop-down list or the Name Box, and Excel answers that the reference isn't valid. What it points to no longer exists, or is not written that way.
What the message says
Excel received a cell address or a name it cannot resolve.
Why it appears
- A defined name equal to #REF!, called by a drop-down list or a formula.
- A hyperlink to a renamed or deleted sheet.
- A reference beyond the sheet's limits (column after XFD, row after 1,048,576), often in an old converted .xls workbook.
- A name that looks like a cell address ("TAX2024" is the cell in column TAX, row 2024).
Making it go away
- Formulas, Name Manager: fix or delete the names equal to #REF!.
- Fix the hyperlink's target.
- Rename a name that looks like a cell ("Tax_2024").
The tool that handles it
The health check lists broken names and removes them; the formula audit finds the #REF! references in cells.
Frequently asked questions
- Why does Excel refuse the name "TAX2024"?
- Because it is also a cell address: column TAX exists, before XFD. A name must not be readable as an address.