Why duplicate emails matter
- The same person receives your campaign twice — a quick route to unsubscribes and spam complaints.
- Email platforms often bill by contact, so duplicates cost money.
- CRMs use the email address to match contacts; duplicates in one import file can overwrite each other unpredictably.
- Open and click rates are understated when one person counts as two.
Clean first, then deduplicate
The report already ignores capitals and surrounding spaces when counting duplicates. When you apply the email fix together with deduplication, addresses are cleaned first — lowercased, spaces removed, and wrappers like “mailto:” or “Asha Rao <asha@example.com>” reduced to the address itself — so duplicates hidden by formatting are removed too.
Lowercasing is safe in practice: although the part before the @ is technically case-sensitive, virtually every email provider treats it case-insensitively.
Keeping the best contact record
When two rows share an email, they often hold different details — one has a phone number, the other a company name. Choose “Keep the most complete row” to keep the row with the fewest empty fields. Rows without any email are never removed as duplicates.