Convert CSV to WAB

Legacy software such as Outlook Express may require a .wab address-book file instead of a CSV contact table. The conversion is therefore used mainly to move contacts into an older Windows installation that still supports Windows Address Book.

What the CSV format is

CSV (comma-separated values) is a plain-text table used to exchange contacts between spreadsheet programs, email clients, customer-management systems, and phone-export tools. Each row usually represents one contact, and the first row contains field names such as First Name, Last Name, Email Address, Business Phone, and Street.

CSV has no universal schema. Exporters can use different delimiters, character encodings, quotation marks, field names, and rules for representing multiple phone numbers or addresses.

What the WAB format is

WAB (Windows Address Book) is a proprietary contact-database format used by Outlook Express and older Windows Address Book software, particularly on Windows XP. A .wab file contains structured contacts and address-book data that compatible legacy programs can open.

WAB is not a current interchange format and is not directly supported by modern Outlook, Google Contacts, or most current mail clients. Its practical advantage over CSV is limited to compatible legacy software, which can retain its own contact fields and address-book structure.

Convert with Outlook Express

Outlook Express is discontinued. Use it only on an existing legacy installation or an isolated Windows XP virtual machine; do not connect an unpatched legacy system to the internet.

1. Make a backup copy of the original CSV.
2. Open the CSV in LibreOffice Calc or Microsoft Excel and confirm that each contact occupies one row and that the first row contains usable headings.
3. In Outlook Express, select File → Import → Other Address Book.
4. Choose Text File (Comma Separated Values), select the CSV, and start the import.
5. Use the field-mapping screen to assign each source column to the appropriate Outlook Express field. Leave unsupported or irrelevant columns unmapped.
6. Inspect several imported contacts, including names, email addresses, telephone numbers, postal fields, and accented characters.
7. Select File → Export → Address Book, choose the WAB export option if it is shown, select a destination, and save the resulting .wab file.

Close Outlook Express before copying the WAB file, because the program may keep the address book open. On a compatible installation, use File → Import → Address Book to load the file. Menu wording can vary slightly between Outlook Express releases.

Prepare and check the CSV

When opening the file in LibreOffice Calc, select the correct character set, delimiter, and text qualifier in the import dialog. Set telephone numbers, postal codes, and other identifier-like values to text before saving; spreadsheet software can otherwise remove leading zeroes or convert values to dates.

If the source stores a full name in one column, split it only when the Outlook Express mapping requires separate first-name and surname fields. Remove formulas by saving plain values, and avoid changing the original file. If accented characters are corrupted, retry the import with the encoding used by the source and legacy system, such as UTF-8 or Windows-1252.

Compatibility limits

The conversion is not necessarily lossless. Custom columns, contact photos, categories, notes, multiple addresses, mailing lists, duplicate records, and unsupported phone fields may be ignored or require manual correction. CSV does not define how these values should be stored, and WAB implementations differ between legacy Windows versions.

Modern Outlook can import CSV contacts, but it does not normally create a WAB file. LibreOffice Calc or Excel can clean and reshape the source data, but neither application exports WAB.

There is no broadly reliable modern online service that preserves arbitrary CSV fields in a WAB database. Online services that claim to perform this conversion require uploading names, email addresses, telephone numbers, and postal data, and may produce files that only one legacy WAB implementation can open. Keep the original CSV as the authoritative backup and verify the exported file in the exact legacy program that will use it.