We are facing an issue with duplicate rules on contact. When we create a new matching rule like below

Please find the below rules setup. (Contact: MobilePhoneEXACTMatchBlank = FALSE) OR (Contact: EmailEXACTMatchBlank = FALSE)

Below error message we get when we try to activate the rule.

Error Message Received : However, we can't activate the rule because it defines an unusually large number of records as possible duplicates. Specifically, take a closer look at these fields.

Please let us know if you have any hints.

2 Answers 2


The error message is clear. You can't enable this rule because there are too many records that match these conditions. You will need to create a more specific matching rule to reduce eligible records or identify records that trigger this rule and modify them.


You are facing this issue because the matching rule is being evaluated upon your existing records in your org before activation, and it seems that there are already too many duplicates matching the conditions in your case.

Matching rules are designed to find "duplicates" in your org, matching the criterias you define, you will need to add more specificity to them (i.e. FirstName, LastName, etc..) We have faced this issue recently, we decided to go deeper on the matching criterias, with a business approach (what really is a duplicate in our business context ?)

You need to consider the business value of the matching rule in your project's context, is it relevant to only use Email OR Mobile Phone as a reference ? Isn't it more suitable to use more criteria ? "AND" logic ? etc..

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