Tuesday, February 21, 2023


Sleep Aid Icon

AOP endpoint 42

What is "AOP.OutboxNotEmpty spu_queue_overflow_ep42" and why does it keep waking my Mac up?

Tuesday, February 21, 2023 - Sam Rowlands

Some 14" and 16" M1 MacBook Pros get woken up by whatever this is, but the quest to find and slay this beast has been a long one.

I don't have one of these Macs, nor have I been able to find a way to rent one in Taiwan. I've resorted to queuing up tests, and running them when I travel into the nearest big city, which is 1.5 ~ 2 hours drive each way.

What is AOP.OutboxNotEmpty spu_queue_overflow_ep42?

At this point it is easier to say what I do know about this, as there is still a lot I don't know.

This information alone isn't helpful, lets see if I can find the driver, perhaps that will be more forthcoming?"

Finding "com.apple.driver.AppleSPU"...

Poking the driver...

Looking at the driver in TextEdit (so I can see strings), I see references to various events or methods for AppleSPUHIDDriver, that gives an idea of what the device's functionality might be.

So which is it, or is it all of them... I don't know to be honest, my gut tells me it might be to do with the charger, as I couldn't imagine why the Mac would need to wake for any other reason. I do know that previous models will wake if the power state changes, i.e. connecting or disconnecting a charger.

Can anyone fact check for me?

Do you know for sure what "AOP.OutboxNotEmpty spu_queue_overflow_ep42" is and can let me know? Use the Contact Us page.