If we stored all of our information on disks that could be wiped clean by electromagnetic pulses, and then had a war in which the principle weapons at hand produced electromagnetic pulses, how much information do you think would be left? How long has your last computer lasted you? How long do you think it would recognizably remain a computer after nuclear strike? Do you know how a car works well enough to perform maintenance on one after all the supply lines are cut? Or would it lay fallow, turning to rust, the world reclaiming it's minerals for the next great civilization? Oh, what I'd give to see the library at Alexandria before the fire. It might have contained the previous civilization's knowledge, or what atleast remained of it that was transferred onto paper. But even books decay. How many of you have books from even a century ago? The elements turn them to dust.

Ah, that's the clincher!
I can't remember where i read it, but there was a study done that tried exactly that.
They analyzed what would be left of a modern city after 10,000 years.
Apart from some glass, & deposits of rare metals here & there, absolutely nothing would remain.

So IMO it could easily have happened several times already.
Scary or what?

The greatest civilizations in the world, reducing eachother to molten, radioactive rubble, blowing mankind back to the stone-age. Maybe next time, they'll figure out how to not kill each other.