Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794673912)

[Liam O’Connor]

Following the recent point release update, my system has encountered intermittent sleep/wake panics. The panic log cites IOPlatformPluginFamily and AppleThunderboltNHI assertions.

I have already tested clearing NVRAM, booted in Safe Mode to isolate third-party kexts, and disabled Power Nap. Has anyone isolated whether this is linked to external DisplayPort docks or an APFS snapshot indexing bottleneck?

[Ethan Carter]

The AppleThunderboltNHI assertion during wake strongly suggests a Thunderbolt controller firmware state mismatch rather than storage or Bluetooth subsystems; verify the dock’s PD controller firmware via system_profiler SPThunderboltDataType | grep -A2 "Firmware" and cross-reference with the vendor’s Sequoia 15.1 compatibility matrix. If the dock presents multiple DisplayPort MST streams, disable IOThunderboltSwitchType power management in /Library/Preferences/com.apple.iokit.IOThunderbolt.plist (requires SIP disable) to prevent the NHI from asserting during link retraining. Concurrently, rule out APFS snapshot metadata stalls by running sudo log show --predicate 'subsystem == "com.apple.apfs"' --last 1h | grep -i "snapshot|trim" immediately after a wake event—indexing bottlenecks manifest as diskarbitrationd timeouts, not NHI panics.

iPhone 16 Pro Max | AirPods Max USB-C

San Diego, CA | "Turn off Low Power Mode when debugging iCloud Photos stalls."

[Emily Hart]

The IOPlatformPluginFamily backtrace indicates an X86PlatformPlugin or AppleACPIPlatform mismatch handling _PTS/_WAK ACPI methods when the Thunderbolt NHI re-enumerates; extract the DSDT with sudo ioreg -l -p IODeviceTree | grep -A20 "DSDT" and check for Method (_PTS) referencing NHI0 or XHC1 without proper SleepType guards. A clean test: boot with nv_disable=1 (if dGPU present) and tbtdisable=1 to isolate whether the panic persists without Thunderbolt enumeration—this eliminates Watch/iPad continuity handoff as variables. Battery health is irrelevant here; the panic occurs in kernel space before powerd evaluates BatteryHealth keys.

iPad Pro 13″ M4 | Apple Watch Ultra 2 | iPhone 15 Pro

Toronto, ON | "Battery cycle count beats random percentage guesses."

[Hannah Brooks]

Migrate the diagnostic focus to the Thunderbolt NHI’s IOThunderboltController::handleLinkEvent() path: capture a kernel debug boot (boot-args="debug=0x144 kextlog=0xfff kdp_match_name=en0") and trigger a controlled sleep/wake cycle while logging via log stream --level debug --predicate 'process == "kernel" && eventMessage contains "Thunderbolt"'. The panic log’s AppleThunderboltNHI::assert() typically maps to kIONHIFatalError during IOThunderboltPort::handleHotPlug()—correlate the timestamp with pmset -g log | grep -e "Wake|Sleep" -A5 to confirm whether the dock’s USB-C billboard device triggers a spurious hot-plug during DarkWake. No user-space app containers (Notes, Mail, Discussions) load kexts capable of triggering this NHI assertion path.

MacBook Air M2 (16GB / 512GB) | iPad mini 7

Portland, OR | "Export solved community threads to PDF while they load."

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