Direct answer
Select the complete contact table, use Data > Remove Duplicates and select the email column as the key. Save a copy first so names and other columns stay attached to the correct row.
More questions and answers
How do I check whether an Excel email address actually exists?
Excel can flag malformed text but cannot reliably confirm that a particular mailbox exists. Export the addresses and run an email verifier for domain or mailbox-level signals.
How do I remove spaces before and after emails in Excel?
In a helper column, use =LOWER(TRIM(A2)) for ordinary spaces. For nonbreaking spaces, replace CHAR(160) before trimming, then check the output and paste values back carefully.
How do I highlight invalid email formats in Excel?
A formula can flag a missing at-sign or domain, but basic formulas miss many malformed addresses and cannot test inbox existence. Follow the format check with verification.
How do I remove all emails from one domain in Excel?
Extract the text after @ into a helper column or use a text filter ending with the target domain, then review rows before removing them. Keep a copy of excluded records.
Why does Excel say two identical emails are different?
Look for trailing spaces, nonbreaking spaces, inconsistent case or invisible characters. Normalise in a helper column and compare that field instead of the displayed text.
How do I get the cleaned email list back into Excel?
Download the results with status columns, import them into Excel, and merge against the original table using a stable email or contact ID. Review unmatched rows before using the list.