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Why am I seeing "Identical recipients detected"?

Explains the identical recipients warning that appears when your spreadsheet contains duplicate email addresses, and how to resolve it.

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What This Warning Means

When you upload a spreadsheet that contains the same email address in multiple rows, SecureMailMerge will show a warning that identical recipients have been detected. This means that without action, some recipients would receive the same email more than once.

Why It Happens

This usually occurs when:

  • Your spreadsheet was exported from a system that created duplicate entries
  • You merged multiple lists without removing overlaps
  • The same person appears with slight variations (e.g. extra spaces or different capitalization — SecureMailMerge catches these too)

Your Options

When this warning appears, you have two choices:

1. Remove the duplicates and send one email per recipient

This is the most common choice. Go back to your spreadsheet and remove duplicate rows so each email address only appears once. Most spreadsheet applications have a built-in “Remove Duplicates” feature:

  • Excel: Select your data → Data tab → Remove Duplicates
  • Google Sheets: Select your data → Data menu → Data cleanup → Remove duplicates

After cleaning up, re-upload the spreadsheet and the warning will disappear.

2. Use Many-to-One mode to combine rows into a single email

If the duplicate rows are intentional — for example, each row contains a different order or line item for the same person — you can use the Many-to-One feature to group all rows for the same recipient into a single email containing a table of their data.

When you see the warning, SecureMailMerge will offer you the option to switch to many-to-one mode directly.

Still Having Issues?

If you’ve removed duplicates but still see the warning, check for hidden whitespace or formatting differences in your email column. Try copying the email column into a new column using a TRIM() and LOWER() formula to clean up any inconsistencies.