What prevents duplicates in the customer register?

When the same customer appears three times, no one knows which record is correct. People then start keeping their own separate lists, and that is where the decline begins.

Use the organization number as the key

For Norwegian businesses, the organization number is the only truly unique identifier. Company names can be written in dozens of ways, with or without AS, and with or without periods. Add the organization number to the company record, make it searchable, and use it as the key when integrating with the accounting system.

Enable duplicate detection — and follow up on what it finds

Dynamics 365 has built-in duplicate detection rules that alert users when saving. They only help if someone actually reviews and resolves the matches. Establish a regular routine—half an hour a month is more than enough—and assign responsibility to one person. Without an owner, the alerts will simply be dismissed.

Address the cause, not just the symptom

Duplicates rarely arise from carelessness. They arise because it is easier to create a new record than to find the existing one. If the search is slow or produces poor results, people will create a new record—every time. Test for yourself how long it takes to find a customer you know exists. If it takes more than a few seconds, that is where the problem lies.

And clean up before migration, not after. Duplicates carried over into a new system are assigned new IDs and become significantly harder to merge.