Convert NBU to CSV

A Nokia backup may contain contacts that must be edited in Excel, imported into a CRM, or moved to another address book. Extracting those records to CSV makes them usable by spreadsheet and contact-management software.

What the NBU format is

NBU is the proprietary Nokia Backup File format created by Nokia PC Suite and Nokia Suite for compatible Nokia phones. An .nbu file is a container that may include contacts, calendar entries, messages, notes, bookmarks, and other phone data; it is not normally a contacts-only file.

NBU files are mainly found in backups of older Nokia phones. Spreadsheet applications cannot read the format directly, so contacts must first be extracted with software that understands Nokia backup records.

What the CSV format is

CSV stores tabular data as rows and columns separated by commas or another delimiter. A contacts CSV can contain names, companies, telephone numbers, email addresses, postal addresses, and notes.

CSV files can be edited in Microsoft Excel, LibreOffice Calc, or Google Sheets and imported into many CRMs, email clients, and address-book services. CSV does not reliably preserve vCard features such as contact photos, custom property types, relationship fields, or the original labels for multiple telephone numbers and email addresses.

How to convert NBU to CSV

The most practical desktop workflow is NBUExplorer → vCard → CSV. NBUExplorer is an older Windows utility designed to open Nokia backup files and extract supported records, including contacts, as .vcf vCards.

1. Copy the original .nbu file and work on the copy.
2. Open the copy in NBUExplorer.
3. Open the contacts section, select the required contacts, and use its extract or export command to save them as .vcf. Menu names and supported record types vary by NBU version and phone model.
4. Open Thunderbird's Address Book and import the .vcf file. Verify names, telephone numbers, email addresses, and notes.
5. Select the imported address book and use its export command, choosing CSV as the output format.
6. Open the CSV in Excel or LibreOffice Calc through the import dialog. Select the correct delimiter and use UTF-8 encoding when available.

For a large export, a dedicated vCard-to-CSV desktop utility can replace Thunderbird, but it must support the vCard version produced by NBUExplorer and provide field-mapping options. Keep the vCard until the CSV has been checked.

If an installed copy of Nokia Suite can still read the backup, another route is to restore or synchronize contacts with Microsoft Outlook, then use File → Open & Export → Import/Export → Export to a file → Comma Separated Values. This depends on the Nokia Suite version, Outlook configuration, phone model, and Windows compatibility, so it is less predictable than direct extraction.

Online conversion options

General online converters normally cannot interpret the proprietary contents of an .nbu file. An online service is useful only after NBUExplorer has produced a .vcf file: choose a reputable converter that explicitly lists VCF or vCard as the input and CSV as the output, upload the extracted file, configure delimiter and encoding, and download the result.

Do not upload an NBU, VCF, or CSV containing private contacts unless the service's retention and deletion terms are acceptable. The desktop NBUExplorer-to-vCard-to-CSV workflow keeps the address book local.

Quality and compatibility limits

The result depends on the Nokia phone model, backup version, backup settings, and records supported by the extraction tool. Some NBU files contain no contacts, and unsupported records may be omitted without producing a complete export. If NBUExplorer cannot open the file, try the Nokia PC Suite or Nokia Suite version associated with the original phone and backup.

Inspect the CSV before importing it elsewhere. Check duplicate contacts, country-code formatting, leading zeros, line breaks in notes, and columns containing multiple phone numbers or email addresses. Format telephone columns as text because Excel and similar programs can remove leading zeros or display long numbers in scientific notation.