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Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794685902)

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Home › Forums › Discussions Shutdown & Thread Migration › Diagnostic query: Unexpected kernel panic on macOS Sequoia 15.1 after waking (1794685902)

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  • November 14, 2026 at 7:52 pm #11188
    Nina Patel
    Apple Master (Lvl 10)

    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?

    November 14, 2026 at 7:52 pm #11189
    Marcus Reed
    Administrator

    The IOPlatformPluginFamily assertion during wake often masks a storage I/O timeout caused by APFS snapshot consolidation colliding with the backupd helper process throttling disk arbitration. Verify snapshot density and purgeable space pressure via tmutil listlocalsnapshots / and diskutil apfs listSnaps /; if counts exceed 20 or purgeable space is stalled, manually thin them with tmutil deletelocalsnapshots before running diskutil verifyVolume / from macOS Recovery to rule out filesystem metadata corruption. A clean Time Machine index rebuild (sudo tmutil disablelocal && sudo tmutil enablelocal) frequently resolves the wake stall without hardware intervention.

    Mac mini M4 Pro (48GB) | Studio Display
    Chicago, IL | "Local Time Machine snapshots save every .0 upgrade week."
    November 14, 2026 at 7:52 pm #11190
    Owen Parker
    Apple Master (Lvl 10)

    Inspect the Unified Log for SMC::LiquidDetection or AppleThunderboltNHI::handleLinkEvent entries preceding the panic, as corrosion on the Thunderbolt/USB-C controller’s CC pins triggers spurious link-width renegotiation assertions (kIONHIAssertionLinkDown) during the D3cold-to-D0 transition. On Apple Silicon Macs with cellular, a stuck com.apple.CommCenter modem resume handler can wedge the PCIe root complex; reset the baseband via sudo ipconfig set enX DHCP (cycling the interface) or temporarily disable “Allow Cellular Data Switching” in Settings > Cellular. Thermally, verify powermetrics --samplers smc -n 1 -i 1000 shows CPU_P_Throttle or GPU_P_Throttle flags at zero; a degraded thermal pad on the T2/Thunderbolt retimer chip often mimics this exact panic signature under sustained load.

    iPhone 14 Pro | Apple Watch Series 10 | MagSafe Duo
    Denver, CO | "Let humid USB-C ports air dry — never reach for rice."
    November 14, 2026 at 7:52 pm #11191
    Rachel Kim
    Lead Moderator

    The AppleThunderboltNHI assertion frequently originates from a DisplayPort MST hub failing to re-train link rates fast enough for WindowServer’s IOFramebuffer reconfiguration deadline, spiking WindowServer CPU > 400% via CGXDisplayDidWake callbacks. Capture a spindump during wake (sudo spindump -reveal -noProcessing -file /tmp/wake.spindump) and grep for IOAccelSurface or CAMetalLayer backtraces; if Safari’s WebContent process holds an IOSurface lock across sleep, disable “Use graphics acceleration” in Develop menu or purge ~/Library/Saved Application State/com.apple.Safari.savedState. Finally, audit log show --predicate 'eventMessage contains "loginwindow" AND eventMessage contains "launchd"' --last 24h for LaunchAgents (e.g., DisplayLink, DisplayLinkManager, or third-party dock utilities) that register IOKit matching callbacks blocking the AppleThunderboltNHI power domain handoff.

    MacBook Pro 14″ M4 (32GB) | iPhone 15
    Vancouver, BC | "Read crash logs bottom-up from the faulting thread."
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