Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794600897)

[Rachel Kim]

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?

[Alex Tanner]

The AppleThunderboltNHI assertion often stems from a Thunderbolt Security Level mismatch (e.g., “User” vs “Secure” mode) preventing DMA authorization during the wake transition, effectively treating the dock as an untrusted device. Verify the active security policy and connected device ACLs via system_profiler SPThunderboltDataType | grep -A 5 "Security Level" and ensure the dock’s firmware is current. If FileVault is enabled, confirm the Secure Enclave key hierarchy isn’t stalling during the power state handoff by checking log show --predicate 'subsystem == "com.apple.iokit.IOThunderboltFamily"' --last 1h. A corrupt com.apple.iokit.IOThunderboltFamily preference plist in /Library/Preferences/ can also persist bad ACLs; delete it and reboot to force re-enumeration.

MacBook Air 15″ M3 (24GB) | AirPods Pro 2 USB-C

Boston, MA | "Keep two trusted devices active before setting a Recovery Key."

[Claire Bennett]

The IOPlatformPluginFamily panic frequently correlates with a failed USB-PD / Thunderbolt power contract renegotiation upon wake, where the dock fails to source the negotiated voltage (e.g., 20V/5A) before the CPU exits C-state, triggering a watchdog timeout. Capture the power assertion timeline with pmset -g log | grep -e "Wake Requests" -e "DarkWake" -e "Thunderbolt" -e "PD" | tail -30 to identify stalled handshakes. Update the dock/DisplayPort adapter firmware via the vendor’s macOS utility—many CalDigit/OWC/Belkin docks shipped with 2023 PD controllers requiring patches for Sequoia’s revised ApplePMGR driver. Disable “Wake for network access” and “Power Nap” explicitly via sudo pmset -a powernap 0 wom 0 to isolate if the PD controller is the wake source.

MacBook Pro 16″ M2 Max | iPhone 16 Plus

London, UK | "Swap the USB-C cable before blaming the logic board."

[Owen Parker]

Inspect the Thunderbolt/USB-C port ingress sensors (SMC keys TC0C, TC1C for port thermals; ALV0 for liquid) via sudo powermetrics --samplers smc -n 1 -i 1000 immediately post-wake; a rapid thermal spike (>15°C delta) or asserted liquid flag on the NHI controller’s retimer IC will trigger a kernel panic to protect the SoC. Corrosion on the dock’s CC/SBU pins creates high resistance, confusing the AppleThunderboltNHI state machine during link training—clean ports with 99% IPA and inspect under magnification. If the panic log shows AppleSMC::handleThermalEvent preceding the NHI assertion, the issue is thermal runaway in the Titan/Thunderbolt controller, requiring a logic board or dock replacement rather than an OS fix.

iPhone 14 Pro | Apple Watch Series 10 | MagSafe Duo

Denver, CO | "Let humid USB-C ports air dry — never reach for rice."

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