When we try to come up with a plausible 'lost history' situation, we run into a few limitations that are quite hard to work around without essentially falling back on 'a wizard did it'.
First and foremost, we have a fairly solid fossil and genetic record that lets us set an early limit for anatomically modern humans at ~200k years. Even if we take liberty with the current anthropological understanding of human development and history, it's hard to justify intelligent humanoids that would be capable of civilization more than ~1MY in history. Clearly, if we're going fantastical (elves, etc) or way out there (dinosaur cities) this limit is irrelevant but let's treat a million years as the 'cap' for the sake of argument.
Second, while we can find ways to handwave away most traces of civilization (more on that later), we would absolutely know if any previous civilization had discovered nuclear power. Discovering nuclear power creates isotopes and traces that don't naturally exist and couldn't be hidden or wiped away. There are places in our civilization where steel and other materials from the pre-atomic age are used for scientific instruments because they aren't contaminated and don't interfere with experiments. There are other chemical processes that would almost certainly leave detectable traces, but nuclear power is the most obvious one.
It would be quite improbable for a civilization to reach our current level of technology without discovering nuclear power. Not entirely impossible, but quite improbable.
Third, a modern society leaves large-scale traces. Things like cities, roads, railroads, buildings, piers and breakwaters, mines, and countless other artifacts that would be readily obvious - even after tens or hundreds of thousands of years - as remnants of some kind of civilization. A city could maybe be lost to a jungle or cataclysm, but not the number of cities and infrastructure required for a modern society to function. 693
While you can maybe justify an agrarian civilization, even a classical Greek or Roman civilization would leave clearly artificial artifacts for tens or hundreds of thousands of years.
Now, on the other hand we have a big card up our sleeve - ice ages. There have been approximately ten of them in the past million years, and the massive glaciation gives a plausible way for the earth to be scoured clean. Roads and cities? Scraped away and mixed in with or covered in with glacial deposits. Cement would be ground to dust. Objects and buildings would be erased wherever they are covered by glacier.
The biggest problem with ice ages scouring everything clean is that glaciers don't cover the entire earth. The last major glaciation stopped at roughly 40* N latitude in North America, which leaves everything south of the Ohio River untouched.
Civilization around the tropics could be swallowed up by the jungle or other growth, but that still leaves a wide temperate band. We've also cleared enough jungle - and yes, found some traces of earlier (hundreds / thousands of year old) civilization that have been swallowed up but nothing that would be a shocking technology level.
So basically, it's hard to justify. One possibility in a sci-fi setting would be that we are a lost alien colony / our ancestors were crew of a crashed starship. The colony broke down for whatever reason (plague, bad luck, warfare, etc), and over the course of a few generations basically lost civilization and later regained it. This makes it hard to justify the fossil and genetic record, but it seems like the most plausible way that there could be a high technology society / civilization that existed before modern civilization. 208