# 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.

## 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](https://www.securemailmerge.com/help/sending-mail-merge-with-many-to-one/) 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.