Most laptops use Lithium-Ion type battery packs. While hugely efficient, they do have the issue that if charged incorrectly, or allowed to discharge too completely, they will swell (or occasionally worse, explode). It also can simply happen due to the battery becoming old.
The swelling is in fact due to the release of gasses by the electrolytes used in the cells. As they are sealed, the gas has nowhere to go, and therefore the swelling.
This line of MacBooks happens to have the unfortunate design flaw that the battery resides below the switch used by the trackpad - so if/when the battery swells, the button is clicked from below, and sometimes even left permanently clicked (which is why you would see your mouse completely stop working for clicking).
Luckily the solution is fairly simple, and I you're willing to go with a non-Apple product, inexpensive. I replaced my pack with one from eBay (a third-party China made pack) for under $30, and it has worked perfectly ever since! Plus, you get the added bonus of getting your battery life back, so it really is a no-brainer!
This always drove me nuts about laptops with trackpads too. I never had a good solution.
由 Taylor Arnicar 完成的
Oh ok, that has never happened to me on my Macbook. That's not supposed to happen under slight pressure from your hand laying on the topcase. I would remove the topcase and have a look at the ribbon cable and check clean up around the creases surrounding the button itself.
由 Majesty 完成的
I have the same problem. But, why the battery? How come? For the sake of simple curiosity, someone could explain? Thanks.
由 Modima65 完成的
Some of the other answers have more detailed descriptions, but the idea is that the battery pack swells as it gets old, and since it sits under the trackpad, it pushes up, causing the trackpad to click when you don't mean to.
由 Sterling Hirsh 完成的