Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794706908)

[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?

[Emily Hart]

While Continuity features (Apple Watch Unlock, Universal Control) exercise the Bluetooth HCI and IOBluetoothFamily, they do not invoke AppleThunderboltNHI or IOPlatformPluginFamily power assertions during the dark-wake transition. The panic signature AppleThunderboltNHI::assertionFailed indicates a Thunderbolt controller (TBT/USB4 retimer) firmware handshake failure exiting D3cold, not a battery or Bluetooth subsystem event. CLI Check: system_profiler SPThunderboltDataType | grep -A2 "Firmware Version" — verify the controller NVM is at the latest Apple-shipped version (e.g., 29.1+ for Titan Ridge/Calypso); if outdated, force a DFU firmware update via sudo /usr/libexec/PlistBuddy -c "Print :IOKitPersonalities:AppleThunderboltNHI:FirmwareVersion" /System/Library/Extensions/IOThunderboltFamily.kext/Contents/PlugIns/AppleThunderboltNHI.kext/Contents/Info.plist comparison against ioreg -l -w0 | grep -i firmwareversion.

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

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

[Hannah Brooks]

User-space application migrations (Mail envelope index rebuilds, Notes CloudKit sync) generate standard APFS transaction pressure but cannot trigger a kpanic inside IOPlatformPluginFamily::getPlatformPlugin unless the hibernation image (/private/var/vm/sleepimage) is corrupted or the APFS snapshot metadata for the boot volume is inconsistent during the hibernate_teardown path. CLI Check: log show --predicate 'subsystem == "com.apple.iokit.IOPlatformPluginFamily"' --style syslog --last 1h | grep -i "assertion|throttle|NHI" to isolate the specific policy assertion (e.g., kIOPMAssertionTypePreventUserIdleDisplaySleep vs kIOPMThunderboltAssertion); simultaneously verify APFS snapshot integrity via diskutil apfs listSnapshots / and ensure tmutil thinlocalsnapshots / 999999999999 4 completes without I/O errors on the boot volume.

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

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

[Ethan Carter]

Background photolibraryd I/O or bluetoothd reconnection storms post-wake manifest as userspace CPU spikes (top -o cpu), not kernel assertions in AppleThunderboltNHI::handleInterrupt or IOPlatformPlugin::dispatchPolicy. The panic context IOPlatformPluginFamily + AppleThunderboltNHI specifically implicates the ACPI _WAK/_PTS method execution order or the Thunderbolt NHI mailbox doorbell register timeout (kNHITimeoutMs) during PCIe link retraining (L0s/L1 exit). Hardware Recovery Step: Disconnect all Thunderbolt/USB4 devices (including DisplayPort alt-mode docks) and measure wake latency via pmset -g log | grep -e "Wake Request" -e "DarkWake" -e "Full Wake" | tail -20; if stable, re-introduce the dock and capture a sysdiagnose immediately post-wake (sudo sysdiagnose -u) to inspect AppleThunderboltNHI register dumps (NHI_INT_STATUS, NHI_LINK_STATUS) for LINK_DOWN or FLR_TIMEOUT flags indicating a dock-side LTSSM failure.

iPhone 16 Pro Max | AirPods Max USB-C

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

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