"This workbook contains links to external sources"
Every time the file opens, Excel offers to update links to a file nobody can find any more. The message comes back as long as the link exists, even hidden in a name or a format.
What the message says
A formula, a defined name, a drop-down list, a conditional format or a chart in the workbook reads a value from another workbook. Excel asks whether to read it again.
Why it appears
- A formula pointing to another file:
='[Budget 2023.xlsx]Sheet1'!B4, often arrived through a copy and paste between workbooks. - A sheet copied from another workbook, with its defined names still pointing to the original.
- A hidden, unused defined name pointing to a vanished file.
- A drop-down list, a conditional format or a chart whose source is in another file.
Making it go away
- In Excel: Data, Edit Links, Break Link. But the button only breaks formulas: names, lists and formats keep the link, and the message comes back.
- Look for names pointing to another file: Formulas, Name Manager, "Refers To" column.
- Break the links of every formula by replacing them with their last value.
The tool that handles it
Remove external links lists the workbooks targeted with the number of cells depending on them, replaces those formulas with their last value, removes broken names, and says where a link hides in a drop-down list or a chart. The file is read back: every value is the same as before.
Frequently asked questions
- Does breaking links change the values?
- No: each formula is replaced by the value it displayed. Only future updates are lost, which is the point.