What does errno 82 (EPWROFF) mean?

EPWROFF

The failure is tied to device state

EPWROFF identifies a device-power condition, not a malformed request. The operation may be valid for that device when it is awake, attached, and initialized, but impossible while the relevant power domain is off.

Useful diagnosis starts with the device class, power transition, and operation stage. A blind retry can be harmful if it prevents the system from completing an orderly sleep, detach, or power-management transition. Instead, coordinate with the owning framework or driver lifecycle and retry only after the documented ready state is observed.

What to correlate

• Device identifier, active power state, recent sleep/wake or detach events, and the caller’s requested operation.
• Whether the request was submitted during teardown, after a hot-unplug event, or before initialization completed.
• Driver or framework logs that show the power-domain transition around the same timestamp.

References

• Apple XNU: Darwin errno definitions
• Apple system-call reference: EPWROFF

Looking for a different code? Search another status or error code.