Sorry, but no.
Incorrect. We have been through all the possible areas enough to know that some community of human/ape-like creatures aren't living there. This isn't 100 or 200 years ago, when great expanses of America, Canada and South America were yet to be settled or explored.
If we were talking about some small animal, like a mouse or something, then it might be possible. But not something the size of humans.
How exactly do you prove something isn't? How do you want me to prove to you that Bigfoot isn't? People have been searching for it with cameras and video-cameras for decades now. It's been a legend for well over a hundred years. No one yet has come up with any concrete evidence. All we have are some random, blurry camera shots and video that could easily be faked. In all of the research done, amazingly no one has every found any real evidence, like bones, a full body, feces, hair, etc. Nothing.
Do you want me to disprove leprechauns to you to? How about unicorns? I mean, hey, it's possible unicorns exist, and we just haven't seen them, right?
There's nothing left to do but laugh at the notion of a Bigfoot existing.