# Decide whether an FSRM classification rule may replace existing values

> When should an automatic FSRM classification rule re-evaluate an already classified file?

- Canonical URL: https://update.dsesecurity.com/updates/dse-20260908-109-decide-whether-an-fsrm-classification-rule-may-replace-existing-values/
- Publisher: Detection Systems & Engineering (DSE Security)
- Author: DSE Security Editorial Team
- Published: 2026-09-08T18:15:22+00:00
- Modified: 2026-09-08T18:23:26+00:00
- Last reviewed by DSE: 2026-09-08
- Resource type: Guide
- DSE priority: Information
- Topics: IT, Networks & Infrastructure
- Reading time: 1 minutes

## What you need to know

When should an automatic FSRM classification rule re-evaluate an already classified file?

## Potentially affected

Administrators configuring automatic FSRM file classification rules.

## DSE recommendation

Prepare example files representing an unset property, a matching existing value, and a conflicting value.

## Article

## Source facts

An FSRM classification rule assigns one property. By default, Microsoft’s procedure leaves files that already have a property value unchanged. Enabling re-evaluation introduces a choice between replacing an existing value and aggregating the new result with it. Microsoft’s Boolean example shows that aggregation can retain Yes when a rule proposes No, while overwrite changes it to No. [Microsoft documentation](https://learn.microsoft.com/en-us/windows-server/storage/fsrm/create-automatic-classification-rule).

## Applicability

Identify the property, existing values, rule scope, classifier, and downstream consumers. Ask the data owner whether an earlier classification is authoritative, provisional, or intended to be combined with later evaluation.

## DSE recommendation

Prepare example files representing an unset property, a matching existing value, and a conflicting value. Agree on the desired result for each before selecting overwrite or aggregation. Record the rule’s scope and enabled state and have the owner review any planned replacement of existing labels.

## Verification

Run the approved examples through classification and compare the actual property values with the decision table. Re-run the process to inspect re-evaluation behavior. Preserve before-and-after values and resolve any unexpected aggregation result before expanding the rule to additional folders or using its output for another action.

## Official references

[Microsoft Learn: Create an Automatic Classification Rule](https://learn.microsoft.com/en-us/windows-server/storage/fsrm/create-automatic-classification-rule). Source reviewed September 8, 2026.

## Primary reference

- Name: Create an Automatic Classification Rule
- Authority: Microsoft Learn
- URL: https://learn.microsoft.com/en-us/windows-server/storage/fsrm/create-automatic-classification-rule
- Source publication date: Not stated by the source

## Citation and use

Preferred citation: “Decide whether an FSRM classification rule may replace existing values,” DSE Security, https://update.dsesecurity.com/updates/dse-20260908-109-decide-whether-an-fsrm-classification-rule-may-replace-existing-values/
Publishing principles: https://update.dsesecurity.com/updates/dse-updates-editorial-methodology/
Usage and citation policy: https://update.dsesecurity.com/usage/
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