Mail merge not working: the eight real causes

"It won't merge" is usually one of a short list of specific problems. Find your symptom below; each one has a cause and a fix. Work down the list in order — the first three account for most of it.

1. Every page shows the same record

Classic on labels, certificates and anything with several records per page. Word only advances to the next record when it is told to, with a «Next Record» rule between blocks.

Fix: Mailings → Rules → Next Record, placed at the start of each block after the first. On a labels layout, using Update Labels inserts them for you across the whole sheet.

2. The document shows { MERGEFIELD Name } instead of the value

You are looking at field codes, not results. Nothing is broken.

Fix: press Alt+F9 to toggle codes off. If a field stays stubbornly as code after that, select it and press F9 to update it. If it prints as code too, check File → Options → Advanced → Print and untick Print field codes instead of their values.

3. Records are missing from the output

Three usual causes, in order of likelihood:

• A blank row in the middle of the data. Some drivers stop at the first empty row. Sort or delete blanks so the block is continuous.
• A recipient filter left on. Mailings → Edit Recipient List — check every row is ticked and no filter or sort is applied from a previous run.
• The range is stale. If the sheet was set up as a named range or table and rows were added below it, the range never grew. Re-attach the data source.

4. Only the first record merges

You clicked Preview Results and then printed or saved, which outputs the previewed record only. Use Finish & Merge, and check that All is selected rather than Current record.

5. Word cannot find the data source

The connection stores an absolute path. Move, rename or re-sync the workbook — OneDrive and SharePoint do this quietly — and the link breaks. It also breaks when the document is opened on a different computer.

Fix: Mailings → Select Recipients → Use an Existing List and point at the file again. Keep the workbook and the document in the same folder if the pair travels between machines.

6. The workbook is open, or locked by someone else

With some connection methods Word cannot read a workbook that is open for editing, and a file on a shared drive that a colleague has open behaves the same way. Close it everywhere, then merge.

7. Numbers and dates come out wrong

Amounts lose their decimals, dates flip order or turn into a five-digit number. This is not a fault — Word receives the cell's value, never its formatting.

Fix: a formatting switch on the field, a DDE connection, or a text column in Excel. Full instructions in why mail merge changes your numbers and dates.

8. It merges, but into one huge document

This one is not a bug either, and it is the most common complaint of the lot. Finish & Merge → Edit Individual Documents produces a single file containing every record, each in its own section. Word has never had an option for one file per record.

Fix: a macro, a Windows-only add-in, or skip the merge entirely. All three are compared in how to mail merge to separate Word documents.

Still stuck? Check the data first

When the symptom does not match anything above, the spreadsheet is the usual culprit. Before touching Word again:

• Row 1 is column names, and every name is filled in and unique.
• No merged cells anywhere in the data block.
• No blank rows or blank columns inside the block.
• The data is on the first sheet, starting at A1.
• Trailing spaces trimmed — they break matching in ways that are invisible on screen.