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Devices & OS

Reduce OS telemetry on Windows and macOS

Your operating system sends usage and diagnostic data back to Microsoft or Apple, and shows you personalised ads. You can turn off the optional parts and the advertising in a few settings; be clear-eyed that some "required" data cannot be switched off from the interface, so this is about minimising, not reaching zero.

  • Medium threat
  • Time 30 minutes
  • Difficulty Moderate
  • Last verified

What this protects, and what it doesn't

Protects

  • Behavioural usage data: turning off optional diagnostics stops a stream of how-you-use-the-device data going to the vendor.
  • Ad personalisation: disabling the advertising identifier and personalised ads reduces how your activity shapes the ads you see.
  • Tailored suggestions built from your activity: the "tips", "tailored experiences" and typing/inking data that feed vendor profiling can be switched off.

Does not protect

  • Required/essential telemetry remains. On consumer Windows the basic "Required" diagnostic level cannot be disabled through the normal interface; macOS still sends data needed for updates and security.
  • Application-level tracking continues. Browsers, apps and games have their own telemetry that OS settings do not touch.
  • It is not anonymity or network privacy. Your IP, your accounts and your network provider still see what they always did.
  • Signing in with a vendor account re-links much of this. A Microsoft or Apple account ties activity back to you regardless of these toggles.

Prerequisites

  • Administrator access to the PC or Mac you are changing.
  • A few minutes; none of these changes is risky or hard to reverse.

Step by step

  1. Windows: turn off optional diagnostic data

    Windows 11 splits telemetry into two tiers: Required (basic data Microsoft says it needs to keep the device secure and up to date) and Optional (fuller diagnostics about how you use the device). You can turn off the optional tier:

    • Settings → Privacy & security → Diagnostics & feedback → turn off "Send optional diagnostic data".
    • On the same page, turn off "Improve inking and typing" and "Tailored experiences", and use "Delete diagnostic data" to clear what has already been sent.

    Be honest with yourself about the limit: on Windows Home and Pro the Required tier stays on and there is no interface switch to stop it. (Enterprise and Education editions can set diagnostics to a "Security/Off" level through policy, which is out of scope here.)

  2. Windows: switch off the advertising ID and suggestions

    Separately from diagnostics, Windows personalises ads and content from your activity. Turn these off:

    • Settings → Privacy & security → General → turn off the advertising-ID switch ("Let apps show me personalized ads by using my advertising ID"), the language-list switch, and the suggested-content toggles.
    • Settings → Privacy & security → Activity history → turn off storing your activity history on the device, and clear it.
    • Settings → Privacy & security → Search permissions → turn off cloud content search and search history if you do not want them.

  3. macOS: turn off analytics sharing

    On a Mac:

    • System Settings → Privacy & Security → Analytics & Improvements → turn off "Share Mac Analytics" and "Share with app developers" (and any Siri/Dictation improvement or iCloud analytics switch, if shown).
    • System Settings → Privacy & Security → Apple Advertising → turn off "Personalised Ads".

    Apple documents these as opt-in sharing you can decline, but as with Windows, some data for software updates and security is not covered by these switches.

  4. Trim voice assistants and dictation

    Voice features can send audio and transcripts to the vendor. If you do not use them, turn them off, and in any case clear their history:

    • Windows: review Settings → Privacy & security → Speech, and turn off online speech recognition if you do not use it.
    • macOS/iOS: System Settings → Apple Intelligence & Siri (older macOS: Siri & Spotlight) → disable if unused, and clear stored history with "Siri & Dictation History" → Delete in the Siri settings pane.

  5. Know what you have and have not achieved

    After these changes, the optional, profiling and advertising streams are off, which is a real reduction. What remains is the vendor\'s required baseline, plus anything your installed apps send on their own. If you need to go further, that is a job for network-level controls (a filtering DNS resolver that blocks known telemetry domains) and for choosing privacy-respecting apps — not for more OS toggles. Set the expectation accordingly: this minimises the OS\'s own data collection, it does not make the machine silent.

Common mistakes

  • Believing a registry tweak or third-party "telemetry blocker" fully silences Windows; the required tier and many connections persist, and such tools can destabilise updates.
  • Turning off diagnostics but leaving the advertising ID and activity history on, so personalisation continues.
  • Assuming OS settings also stop app and browser telemetry — they do not; handle those separately.
  • Signing in with a vendor account and syncing everything, which re-associates activity with you regardless of these toggles.
  • Expecting zero data flow; the honest goal here is to remove the optional and advertising data, not all of it.

Going further

To cut telemetry that OS settings cannot reach, block known telemetry and tracker domains at the network with a filtering resolver (see Encrypted DNS and Ad and tracker blocking). For phones, the same ideas apply in the mobile OS privacy settings; and to protect the data on the device itself see Full-disk encryption.