Chosen Solution
The mouse button (not the whole trackpad, or the keyboard, but just the mouse button) has decided that it’s permanently depressed, which means I can’t click on anything anymore. It’s definitely a hardware issue; the same thing continues if I boot into Ubuntu. The computer’s too old to merit the couple hundred dollars it would take to replace the whole upper case, so I wanted to see if anyone had any other ideas about how to fix this. Is there a connector somewhere that could have gotten loose? Is there something I can try to clean? Etc. Wild ideas welcome. Thanks!
Well, the trackpad assembly is fully immersed and melted in the topcase, so there’s no way you could act in it. You can try using a piece of paper or something thin enough and move between the button and the trackpad, to see of something got lodged that. Or try the topcase without the battery: a chinese battery I have presses on the topcase for example, making the button “sturdier” at touch. If without battery the button works fine, that means the battery is pushing on the mechanism.
