Known issues
This page collects hardware and macOS issues that can affect Cable Detective users but are not bugs in Cable Detective itself. We list them here for transparency.
Power error or freeze on connect / disconnect — fixed in 1.8.0
What happened
Two users reported their Mac shutting down with a power error, or freezing, when plugging or unplugging a device while Cable Detective was running. Cable Detective is a passive reader — it never writes to a port — but it was reading at the worst possible moment: macOS notifies an app the instant a port controller starts handling a plug event, and Cable Detective answered every one of those notifications by immediately reading that controller's entire property table, while the driver was still mid-transition. A single plug event fires dozens of such notifications.
What changed in 1.8.0
- Nothing is read from inside a macOS notification callback any more. The notification only records that something moved.
- A burst of plug events collapses into a single read that runs only after the port has been quiet for 400 ms.
- The five-second background refresh stands down while a plug event is in flight.
If you hit this on 1.7.0 or earlier, we are sorry — and thank you for the reports. If anything like it survives in 1.8.0, please use Settings → Report a bug (new in 1.8.0) so we get the full port state with it.
macOS kernel panic in AppleHPM on USB-C / DisplayPort hot-swap
What happens
On macOS 26.3.x running on Apple Silicon, plugging or unplugging a USB-C cable to certain external monitors can hard-panic the kernel inside com.apple.driver.AppleHPM. The fault is a type-confusion in AppleHPM's PD ↔ DP-Alt-Mode message marshalling.
Confirmed environment
| Hardware | T8112 (M2 MacBook Air, 24 GB) |
|---|---|
| OS build | 26.3.1 (25D2128) |
| Triggering kext | com.apple.driver.AppleHPM 3.4.4 |
| Reproducibility | Hit 3× in one day on a single machine, identical fault site each time |
Workarounds for end users
- Sleep the Mac before unplugging the monitor —
pmset sleepnow, or close the lid. Drains AppleHPM's event queue. - Use a powered USB-C dock and unplug from the dock side — the laptop's port stays in steady PD state.
- Use HDMI if the monitor offers it — bypasses USB-C PD/DP-Alt-Mode entirely.
Tracking
Full technical writeup including the panic fingerprint and timeline: Arthur-Ficial/cable-detective#2. Filed with Apple Feedback Assistant.
Reporting a different issue
If you hit something not listed here, email [email protected] with the macOS build, Mac model, and a redacted Copy all export from the affected port.