## TL;DR

The import matched on the wrong external ID and merged unrelated records. Stop the import, unmerge what you can, fix the ID mapping, and re-import.

## Error

```text
import merged unrelated records on wrong external id
```

## Steps

1. Stop the import immediately Expected: no more bad merges.
2. Identify the wrongly merged records Expected: you know the scope.
3. Unmerge what the CRM allows; restore the rest from backup Expected: data is repaired.
4. Fix the external ID mapping and re-import Expected: matches are correct.

## When to use

- Import merged unrelated records
- The external ID was wrong

## When not to use

- The ID is right (then check for duplicate ID values)
- Merges were intended (then the match criteria were too loose)

## Tool compatibility

- External IDs
- Data imports

## Variant phrasings

### wrong external id merge

Stop, unmerge, fix the ID mapping.

### import merged unrelated

Same: the external ID pointed at the wrong records.

## Why it happens

External IDs are only unique if the source keeps them unique. Agents trust the column without validating uniqueness.

## Edge cases

- Test the match on a sample before the full import
- Keep an import log to reverse bad merges

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_flQmwTB-0lieEiY9dkjgfg