Windows 11 Privacy: Flip Off Optional Diagnostic Data for Better Privacy

If you value privacy on your PC, the single most important Windows 11 switch to flip is the Send optional diagnostic data toggle — and you should understand precisely what flipping it does, what it does not do, and the safe ways to reduce the diagnostic pipeline between your machine and Microsoft.

Background​

Windows has collected diagnostic data since Windows 10 introduced a far-reaching telemetry model in 2015. Microsoft maintains that telemetry helps keep systems secure, diagnose crashes, and improve the product, but the split between required and optional diagnostic data is central to what a privacy-conscious user can control. Required diagnostic data cannot be fully opted out of on consumer systems; optional diagnostic data can. This distinction matters because optional data includes more detailed usage and browsing signals, while required data covers the minimum telemetry Microsoft considers necessary for security and reliability.
This article walks through what Windows 11 actually collects, the official and practical steps to narrow data collection, how to use Group Policy or the Registry where appropriate, and the trade-offs and risks of disabling telemetry-related services. All procedural steps are verified against Microsoft documentation and reputable Windows-focused guides to ensure accuracy.

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Overview: What Windows 11 collects and what you control​

Required vs Optional diagnostic data​

• Required diagnostic data: basic device configuration, reliability and health signals, and information needed to keep Windows secure and running. Microsoft says this is the minimum necessary to keep the OS functioning and secure. Users cannot opt out of required data using the Settings UI; organizations have policy controls but consumer-level opt-out is limited.
• Optional diagnostic data: additional telemetry that can include app usage, some browsing signals, enhanced crash reports (potentially including memory state), device health and feature usage meant to help product improvements and personalized experiences. This is the data you can stop sending from the Settings app by toggling off Send optional diagnostic data.

What “optional” actually contains​

Optional diagnostic data may contain granular usage events, crash dump fragments, and signals that help Microsoft build product features or targeted suggestions (Tailored experiences). Microsoft documents explicit examples and grouping of optional events and notes that optional data can include memory state when a crash occurs — which may unintentionally include parts of files that were open at the time. That’s one reason why some privacy-focused users are uncomfortable with the collection even when Microsoft says it is anonymized.

Who can fully disable telemetry?​

• Windows 11 Home: you can turn off sending optional diagnostic data via Settings, but you generally cannot disable required diagnostic data entirely through the Settings UI. Registry edits may reduce levels but can be limited by edition and policy. Independent guides and Microsoft’s organizational guidance emphasize that full telemetry turn-off is an enterprise-level control.
• Windows 11 Pro / Enterprise / Education: administrators can use Group Policy or MDM to set diagnostic data levels (including the organizational options that can reduce telemetry to the "Security" level or fully disable it in certain managed scenarios). Group Policy is the supported enterprise pathway.

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How to stop optional diagnostic data (the safe, supported first step)​

This is the first action every privacy-conscious Windows 11 user should take. It reduces data shipped to Microsoft while staying within the supported UI.

• Open Settings (Win + I).
• Go to Privacy & security > Windows permissions > Diagnostics & feedback.
• Under Send optional diagnostic data, switch the toggle to Off.

Turning this toggle off will stop the collection of optional data while required diagnostic data continues to be sent according to Microsoft’s documentation. This is the supported and recommended method for consumer devices.

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The Diagnostic Data Viewer and deleting what Microsoft already has​

Microsoft gives two built-in controls you should use after changing the toggle:

• Diagnostic Data Viewer: enables you to view the diagnostic data Windows is collecting. Microsoft notes turning on data viewing can use up to 1 GB of local disk space and that the viewer holds up to either 1 GB or 30 days of diagnostic history by default (whichever limit comes first). Turn it on, review what’s being collected, then turn it off when finished to reclaim space.
• Delete diagnostic data: a one-click setting in the same Diagnostics & feedback page that requests deletion of the device's diagnostic data stored by Microsoft. Microsoft warns that deleting device data from the UI does not necessarily remove diagnostic data associated with your Microsoft account or copies held by organizational IT services, and that deletion may not be immediate.

Practical steps:

• Settings > Privacy & security > Diagnostics & feedback.
• Turn on View diagnostic data to open the Diagnostic Data Viewer.
• After reviewing, use Delete diagnostic data to remove the device’s diagnostic footprint from Microsoft systems where possible.

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Using Group Policy (Pro, Enterprise, Education) — what it does and exact policy names​

If you're running Windows 11 Pro, Enterprise, or Education and you want a more deterministic control over telemetry, use Group Policy.

• Policy path: Computer Configuration > Administrative Templates > Windows Components > Data Collection and Preview Builds.
• Policy name: Allow Diagnostic Data (older or specific releases might use “Allow Telemetry” wording).
• Policy options and values (per Microsoft documentation):
• 0 = Diagnostic data off (Security)
• 1 = Required (Basic)
• 2 = Enhanced
• 3 = Optional (Full)

Setting the policy determines whether the user can change the setting in Settings and whether optional data is sent. The policy is the correct enterprise method to enforce a telemetry level across many devices. After applying the Group Policy change you should run gpupdate /force or reboot to apply the setting.
Important notes:

• Some newer policies and CSPs (for MDM) exist for enterprise reporting and alignment with services like Desktop Analytics or Update Compliance. These may require specific enrollment and can cause telemetry to be processed under different contractual protections. Do not change these policies lightly on managed devices.

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Registry edits and Home edition caveats​

Advanced users sometimes use the Registry to influence telemetry. The commonly referenced key is:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\DataCollection
Value name: AllowTelemetry (DWORD)
Values typically used:

• 0 = Security (may be available only to enterprise-managed devices)
• 1 = Basic / Required
• 2 = Enhanced
• 3 = Full / Optional

Caveats and warnings:

• Editing the Registry has risks; always back up the Registry and create a system restore point before changing values.
• On many consumer Home installations, setting AllowTelemetry to 0 may be ignored or overridden by system behavior or Microsoft updates — Microsoft’s documentation reserves certain minimal telemetry for system health/security and provides enterprise controls for more restrictive levels. Use the Registry method only if you understand the limitations and possible side effects.

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Disabling telemetry-related services (Connected User Experiences and Telemetry — DiagTrack)​

Many how‑to guides recommend disabling the Connected User Experiences and Telemetry service (service name often shown as Connected User Experiences and Telemetry; binary DiagTrack) and the dmwappushsvc service to stop background telemetry processes. The practical steps are:

• Win + R → services.msc → Enter.
• Find Connected User Experiences and Telemetry → double-click.
• Change Startup type to Disabled → Stop the service → Apply → OK.
• Optionally repeat for dmwappushsvc (WAP push message routing service) if present.

This prevents the service from auto-starting and reduces the immediate background telemetry activity on boot. Independent Windows guides and community forums have widely documented this sequence.
But: There are trade-offs and technical caveats.

• Functionality risk: Some Windows features, diagnostics pipelines, Insider features, or enterprise reporting solutions rely on these services. Disabling them can break or degrade features that depend on background telemetry or push notifications, and may affect managed device compliance. Microsoft’s enterprise documentation highlights that certain analytics and update compliance features rely on diagnostic data and processing settings.
• Not an official “supported” opt-out: Stopping services is a local workaround, not an official Microsoft user-facing opt-out for required diagnostic data. It’s a practical step that privacy-aware users take, but it can have side effects during updates or if Microsoft changes service dependencies.

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What else to toggle for privacy (safe, user-facing controls)​

Turn off or limit additional features in Settings that increase diagnostic or usage signal exposure:

• Privacy & security > Speech: Turn off Online speech recognition.
• Privacy & security > Inking & typing personalization: Turn off Personal inking & typing dictionary.
• Privacy & security > Activity history: Clear and stop sending activity history.
• Privacy & security > Diagnostics & feedback: Turn off Tailored experiences (prevents use of diagnostic data to personalize tips and ads) and set Feedback frequency to Never.

These controls reduce ancillary telemetry and personalization while staying within the supported UI. Several reputable Windows help sites list these steps as part of a privacy hardening checklist.

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The trade-offs: privacy vs. security, support, and compatibility​

Disabling optional telemetry and stopping telemetry services reduces the data Microsoft receives about your device, but that reduction has consequences:

• Security and update quality: Microsoft states that devices remain secure when only required data is sent, but some advanced diagnostics that help identify and fix rare or emerging issues may be reduced. Required telemetry is explicitly intended to preserve baseline security and reliability.
• Feature behavior: Features like Tailored experiences, certain troubleshooting assistants, and some Microsoft services may not work or may provide less helpful guidance. Enterprise services centered around Update Compliance, Desktop Analytics, and other management tooling can be affected if telemetry is reduced or disabled.
• Supportability: If you need vendor or admin support later (especially on work-managed devices), having telemetry disabled may limit the ability of support teams to diagnose problems remotely.
• Updates and policy reapplication: Microsoft periodically updates telemetry implementation and group policy CSPs. A local registry tweak or service stop can be undone or superseded by cumulative updates or group policy refreshes, so these measures are not always permanent without continued maintenance.

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Practical, step-by-step privacy-hardening checklist (prioritized)​

• In Settings > Privacy & security > Diagnostics & feedback, toggle Send optional diagnostic data to Off. This is the single most effective consumer-facing change.
• Turn off Tailored experiences and set Feedback frequency to Never in the same Diagnostics & feedback pane.
• Use Diagnostic Data Viewer to inspect what’s being collected; then use Delete diagnostic data to request removal of existing device diagnostic data from Microsoft systems.
• For Pro/Enterprise/Education: set Allow Diagnostic Data via Group Policy (Computer Configuration > Administrative Templates > Windows Components > Data Collection and Preview Builds) to the desired level. Use 1 (Required) for the minimum Microsoft supports for non-enterprise "Security" scenarios.
• If comfortable and aware of risks, disable the Connected User Experiences and Telemetry (DiagTrack) service and dmwappushsvc — but understand this may break push-based features and enterprise analytics.
• Turn off Online speech recognition, Inking & typing personalization, and clear Activity history.
• Regularly check Settings after major Windows updates to make sure privacy toggles have not been reset.

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Verified technical numbers and one useful data point​

• Microsoft documents that enabling the Diagnostic Data Viewer can use up to 1 GB of disk space and that the average device generates variable telemetry volume (Microsoft has cited specific device-class examples like Surface devices generating roughly 150 KB/day in a dedicated Surface support note; actual volumes will vary by device and configuration). Use the Diagnostic Data Viewer sparingly and turn it off when done to reclaim space.

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When to avoid aggressive telemetry removals​

• On work or school devices under IT management, do not change Group Policy or service states without approval. Enterprise policies and monitoring rely on diagnostic channels for compliance and security.
• If you rely on rapid, accurate remote support or on Microsoft’s advanced troubleshooting features, keep optional telemetry enabled or consult IT about managed telemetry levels.
• If you are part of Windows Insider builds or participate in Microsoft feedback programs, disabling telemetry or related services can prevent your device from reporting Insider telemetry and may exclude it from preview diagnostics.

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Final assessment and recommendations​

• The easy, supported privacy win is to turn off Send optional diagnostic data in Settings and to disable Tailored experiences. This cuts optional telemetry without touching system services and without risking unsupported behavior. It’s the first priority for anyone who cares about privacy.
• For users on Windows 11 Pro, Enterprise, or Education who want firmer control, use Group Policy to set diagnostic levels and consider MDM/CSP options if you manage fleets. That approach is supported and predictable.
• For advanced users who accept the risk of breaking ancillary features, disabling the Connected User Experiences and Telemetry service will reduce background telemetry further — but this is a workaround, not an official opt-out path, and it carries compatibility and support risks. Always document changes and keep backups so you can revert if needed.
• Be mindful that some telemetry — the required diagnostics — is described by Microsoft as necessary for baseline security and is not fully removable on consumer devices through Settings alone. If your threat model treats any remote diagnostic collection as unacceptable, consider using a hardened, privacy-focused OS or a managed environment designed around strict telemetry constraints.

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Windows 11 makes it straightforward to stop the bulk of telemetry that most users find intrusive; the supported Settings controls are the safest place to start. For shoppers, IT admins, and privacy-minded power users, understanding the difference between optional and required diagnostic data, using the built-in Diagnostic Data Viewer and Delete functions, and applying Group Policy where appropriate provides a clear, verified path to reclaiming control over what your PC tells Microsoft.

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Source: Pocket-lint If you care about privacy, you should switch off this Windows 11 setting