Could a mass extinction event leave no trace humans ever existed?

I doubt it. We bury our dead, so the bones would be left behind. Since we preserve some bodies there might be fairly intact corpses, that I am not sure of, I don’t know about embalming. Where the meteor hits it might erase any presence of humans, but the other side of the earth would still have evidence. In fact, some bones might be barely covered when discovered from those who died from the consequence of the meteor.

No, that couldn’t happen.

Yes, it could happen.
It would require an asteroid impact so large, that the entire planet’s crust is liquified, to absorb all the radioactive material that humans produced.
Technically, the Earth itself would still be intact, as in, not shattered into a new asteroid belt.

”...all evidence of human occupation…” consists of so much more than human bodies. Cities, roadways, railways, satellites, anything artifacted (I know that’s probably not a word but you know what I mean) that is left is evidence. Anything that could eradicate all of that would likely have to destroy the entire surface, including all human stuff in the oceans and in orbit.
We have left a pretty intense legacy.

Consider that we have records of very old dinosaurs that were part of a mass extinction 66 million years ago. So I doubt a mass extinction event could be more catostrophic than that one, yet there is still evidence that predates that event.

Plastic will remain for centuries:
http://guardianlv.com/2014/06/a-new-rock-in-hawaii-is-made-of-plastic/

I think we’ve made such an effect on this planet, it would be almost impossible to eradicate everything we’ve done.

Good question!

Let’s give the new user a warm Fluther welcome.

I think there is absolutely no way to erase the human footprint. We even managed to leave our footprints on the moon. The only way to erase any evidence of humanity is something extreme like @ragingoli suggested. Or build a time machine and kill off anything that could have evolved into humans.

When our sun novas, that will probably do it.

Sol will not become a Nova. Merely a red giant

Not likely. Even when the rock we live on boils away under our red giant sun the 2 voyager spacecraft will tumble on. And there’s certain to be more stuff of ours floating between the stars by then. The odds are, if we can survive as a species another 200 years or so, we will certainly escape this planet and very probably this solar system.

Stainless steel artifacts will still stay for 25,000 years.

Regretfully, I have to agree. Not only will bits & pieces of our satellites & probes pollute space for the rest of time, our television & radio transmissions will spread our narcissism through the infinite void until time itself collapses. We are an immortal virus.