macOS kernel return 0xE0020004: meaning and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: the controller cannot perform the requested power change.

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kIOBluetoothNoHCIController

kIOBluetoothHCIPowerStatesNotSupported

Power management capability belongs to the local HCI controller

kIOBluetoothHCIPowerStatesNotSupported means that the HCI controller does not support changing power states through the requested IOBluetooth path. It is a host-adapter capability result, not a GATT attribute error and not a statement about a peripheral's battery or sleep mode.

Apple's IOBluetoothHostController documentation notes that controller power state is a controller property and that only Apple Bluetooth adapters support power off. An application should therefore treat a rejected power transition as a capability boundary rather than repeatedly toggling the controller.

What to check

Record the controller identity, current power state, requested transition, adapter type, macOS version, and whether the operation followed sleep/wake or a transport reattachment.
Use the supported system or API power-management model for that controller; do not substitute a remote-device disconnect for a host-controller power operation.
Keep this result separate from No HCI Controller: here a controller exists, but it does not expose the requested state change.

References

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