How to fix Outlook contact CSV import errors

Most failed contact imports come down to encoding, column headings, delimiters, or one malformed row. Work on a copy, test with a few contacts, and keep the original export untouched.

1. Preserve the original

Duplicate the exported file before editing it. Contact migrations are easier to recover when the source export remains unchanged. Give the working copy a clear name such as contacts-cleaning-copy.csv.

2. Check the encoding

Microsoft recommends UTF-8 because it works across languages and alphabets. If names appear as question marks, diamonds, or other unexpected characters in Outlook's preview, cancel the import and convert the file to UTF-8 first.

In Excel, import the file with Data → From Text/CSV, choose the encoding that displays the names correctly, and save a new copy as CSV UTF-8 (Comma delimited). Do not overwrite the only copy of your source export.

3. Keep the header row

Outlook expects column headings in the first row. Missing, duplicated, or unfamiliar headings can leave fields blank or place data in the wrong destination. Typical contact columns include a name, email address, phone number, company, and notes. Classic Outlook can map source fields during its import wizard; the current Outlook workflow is less forgiving, so a clean header row matters.

4. Confirm the delimiter and row structure

A file may end in .csv but use semicolons or tabs instead of commas. That can make the whole row appear in one column. Quoted commas inside addresses and notes must also be balanced. If the import stops after a specific contact, inspect that row for an unmatched quote or an unexpected line break.

5. Choose a duplicate policy deliberately

Classic Outlook offers three choices: replace duplicates, allow duplicates, or skip duplicate items. None of them can reliably infer which partial record is better in every case. Clean exact duplicates before importing, then choose the Outlook option that matches the quality of your source file.

6. Test a small sample

Create a copy containing the header and a few representative contacts: one with an international phone number, one with non-English characters, and one with multiple populated fields. Import that sample, inspect the results, delete the test contacts if necessary, and only then import the full file.

Clean a sample locally

Contact CSV Doctor Lite detects comma, semicolon, and tab delimiters, recognizes common English and Simplified Chinese contact fields, normalizes email and phone formatting, and merges exact matches by normalized email or phone. Processing happens in your browser; the file is not uploaded.