Need a hand?

Average reply time: 1–3 days · Email is the fastest channel

Before you write

If you can include the following with a bug report, we can usually diagnose it in one round:

• Your Mac model (Apple menu → About This Mac), e.g. "MacBook Pro 16-inch, M3 Pro"
• Your macOS version
• Heatsink version (Heatsink → About Heatsink)
• What you expected to see vs. what you actually saw — a screenshot is gold

Frequently asked questions

Why does each fan show a temperature instead of an RPM?

On Apple Silicon and macOS 14+, Apple gates fan-tach reads behind privileged entitlements that aren't available to sandboxed App Store apps. Rather than fabricate a fake RPM number, Heatsink binds each fan widget to a real on-die temperature sensor — the blade speed, glow color, and HOT/WARM/COOL badge are all driven by that zone's actual measured °C/°F. Hot = fan working harder. The metaphor matches physical reality without making anything up.

My MacBook Air shows "Fanless Chassis." Is that a bug?

No — every M-series MacBook Air is genuinely fanless and uses passive cooling. The dashboard shows a chip diagram with the live die temperatures instead of fan widgets, which is the honest representation of the hardware.

How do I switch to Fahrenheit?

Open Heatsink, then ⌘, (Cmd-comma) to bring up Settings. Under General → Display, pick Fahrenheit. The change propagates to every readout (dashboard, popover, menu bar, status footer, alert notifications) immediately.

How do I get a notification when my Mac gets hot?

Settings → Alerts. Toggle "Notify when a sensor exceeds the threshold," set your threshold, and pick a cooldown. Heatsink will post a local notification when any sensor crosses the line. The cooldown prevents notification spam during a long workload.

What does "PMU tdie6" mean? What about "PMU tcal"?

Hover any sensor row in the rail and the panel at the bottom of the rail will show a one-line description plus the live reading. In short:

• PMU tdieN — On-die temperature sensor on the SoC, reported by the Power Management Unit. Each numbered TDIE corresponds to a region of the chip (CPU clusters, GPU, neural engine).
• PMU tcal — A calibration reference, used internally for accuracy correction. Not the actual chip temperature.
• gas gauge battery — Battery cell temperature from the battery management controller.
• Tp0N — Apple Silicon proximity sensor near specific CPU/GPU cores.
• TC0… / TG0… — CPU / GPU temperatures (proximity, heatsink, or die) — common on Intel Macs.

Does Heatsink send any data to the cloud?

No. Heatsink does not have network access — its sandbox doesn't request it. There is no analytics, no telemetry, no cloud sync, no crash reporting that goes off-device. Sensor data, preferences, and history all stay on your Mac. See the privacy policy for the full breakdown.

Can I run multiple Heatsink dashboards?

No — Heatsink is a single-window app. The dashboard is the same whether you open it from the Dock, the menu-bar popover's "Dashboard" button, or ⌘1. Two windows of the same data add no value, so we don't allow it.

Can Heatsink control my fan speed?

No — Heatsink is read-only. It visualises what's happening; it doesn't override macOS's thermal management. Fan-control utilities on macOS require kernel-level privileges, are not allowed in Mac App Store apps, and risk damaging your hardware if used carelessly. macOS already does a competent job balancing performance and thermals.

Heatsink doesn't show any sensors. What's wrong?

This usually means IOHID returned nothing for our sensor query. Causes we've seen:

• Running on a Mac model older than what we've tested — please email us with your Mac model
• A macOS update that changed sensor exposure — restart usually helps
• Sandbox issue from a corrupted preferences container — quitting and relaunching Heatsink usually fixes it

If none of that helps, send us your Mac model + macOS version and we'll look into it.

Reach us

support@heatsink.uk is the fastest way. We aim to reply within a few days.

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