Dynamics Community Forum Thread Details

Contact Deduplication

Hello Community,

I’m looking to solve a contact deduplication issue for a customer.

There are about 1 million contact records (a massive number of duplicates). They imported spreadsheets into the system over the years without any guidance or best practice on how not to create duplicates.

I have set up Duplicate Detection Rules on the Contact

Go to Settings → Data Management → Duplicate Detection Rules.
Create rules for:
- Contact: Email, Full Name + Mobile, Full Name

How best can I approach these issues - Data deduplication, matching logic, automation, auditing, and preventive controls.

The customer does not allow any third party tool (XRM Toolbox etc) on there tenant.

I would like to automate (Automated Merge) this process and be able to count and log the deletions. All using low code. I’m not a developer.

I look forward to all the support.

Kind regards,

Chi

Categories:

Dynamics 365 general

Power Platform integration

Understanding your current state
Volume: ~1 million contacts, many duplicates.
Root Cause: Historical imports without validation.
Constraints: No third-party tools, must use low-code (Power Automate, OOB features).

for maintain uniqueness :

Consider adding Alternate Keys for Email or Mobile to enforce uniqueness going forward.
Use Exact Match for Email and Mobile, and Fuzzy Match for names if possible.

Deduplication Approach
Since you cannot use XRM Toolbox or external tools, recommened approach would be power automate or data flows:
Option 1: Use Bulk Merge via Power Automate

Create a Power Automate flow:
Trigger: Scheduled or manually.
Action:
Query contacts using List Records with OData filters based on your duplicate detection logic.
Group by Email or Mobile.
For each group:
Keep the oldest or most complete record.
Merge duplicates using the Dataverse Merge action (available in Power Automate).
Log the merge in a custom entity or Excel file for auditing.

Option 2: Use Dataflows for Preprocessing

Use Power Query Dataflows to:

Pull all contacts.
Apply grouping and deduplication logic.
Push cleaned data back into Dataverse.

Automation
you can schedule Power Automate flow to run during off-peak hours.
Use batching to avoid hitting API limits (process in chunks of 5,000 records).

Auditing & Logging
Create a custom entity called “Deduplication Log”:
Fields: Original Record ID, Merged Record ID, Date, User.
In your flow, after merging, create a log entry.
Alternatively, you can write logs to Excel in OneDrive for easy reporting.

Preventive Controls
Enable Duplicate Detection Rules for:
On Create and On Update.

Use Alternate Keys for Email and Mobile.
Train users on proper data entry.
If imports are still happening:
Use Data Import Templates with duplicate detection enabled.

Challenges
Performance: 1 million records will require incremental processing.
Merge logic: Decide which record to keep (oldest, most complete, etc.).
API limits: Use pagination and throttling in Power Automate.

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