The Importance of Duplicate Detection Rules for Microsoft Dynamics 365/CRM Admins, and How to Set them Up

Microsoft Tips

Behind Auditing in Microsoft Dynamics 365/CRM, Duplicate Detection is arguably the most important function for admins to set.

Admins will want to turn Duplicate Detection on and delete duplicates when:

  • A record is created or updated
  • Dynamics 365 goes from offline to online
  • During data imports

Some important Duplicate Detection Rules to follow during this occurrence include:

  • One of the most important and under-utilized tools in CRM
  • Do not rely on System Duplicate Detection Rules
  • Duplicate Detection Rules for Contacts and Lead Contacts
  • If you do not see an Entity available to set a Duplicate Detection Rule for, then the Entity needs to be enabled for Duplicate Detection

To do this, follow these steps …

Microsoft Dynamics 365/CRM Tips

  1. In your system, navigate to Settings > Data Management > Duplicate Detection Settings
  2. A window will pop up once you click – make sure these fields are checked within it …
    • Enable Duplicate Detection
      • When a record is created or updated
      • When Microsoft Dynamics 365 for Outlook goes from offline to online
      • During data import
  3. Click OK

Different Duplication Detection Rules are set up in your system. A very important one is “Contacts with the same email address”.

It’s one of the best ways to detect duplicates in your system because people cannot have the same email address. Every email address is unique.

You may click “email”, “exact match” to locate contacts.

When using this, you will want to check “ignore blank values” so you don’t get empty fields showing up in your results.

Microsoft Dynamics 365/CRM Tips


It’s dually beneficial to click “Ignore Blank Values”, because, if a contact does not have an email associated with them, they will show up as the same person in your results, though they may be clearly different by name identification.

You will also want to leave this field unchecked: “Exclude Inactive Matching Records”.

Why? If you have a former customer, for example, and they start working with you again, and you check this box, you will not have access to any historical data and have to fill in their information all over again.

You will not have a clear visualization of their work history, needs, or past pain points that you could benefit from in a new relationship with them.

Instead of creating it all over again, you can go back in and re-activate it to retain that historical information.

It makes things much easier and faster for everyone involved!

Another field you don’t want to touch is “Case Sensitive”. People tend to misspell while entering information in CRM, much less follow the same Case Sensitivity. It’s human nature!


Best Practices for the Beginner Admin Microsoft Dynamics Tips

Another important rule is “Lead to Contact”.

Lead to Contact is especially important, as you don’t want to get all the way to the qualifying stage only to realize there’s already a contact in your system for this person.

You want to know that when you first create your lead, and this duplicate rule will help you do exactly that.

Email is the way to go to make sure this is executed in the most effective way for your organization and teammates.

You wouldn’t want to do the company name, for example, as it is a fill-in-the-blank and not a lookup-field. Since field types can’t cross, email is still the most effective way.

Leave the same fields unchecked as you would with the first duplicate detection rule we’ve gone over in this post.


Duplicate Detection is a truly dynamic feature of the system we hope you feel more confident taking advantage of after reading this post.

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