[dimfeld]

I had the same thing happen recently, and came across this Youtube video detailing a fix: https://www.youtube.com/watch?v=yFaLyoSQQo0.

Essentially, you open up the mouse and loosen the internal screws on the thumb button a little bit, which moves the board away from the rubber over the button and relieves whatever pressure is keeping it pressed. You need a screwdriver with a T5 Torx bit to open up some of the screws, but overall the procedure is pretty easy and my mouse has been working great ever since.

[scrollaway]

I read the parent's comment, messed with the thumb button, and had the exact same thing happen.

Now I read your comment, slid a screwdriver under the thumb rubber (didn't bother opening the mouse) and that unfucked it.

Man…