I have a 2013 Macbook Pro running MacOS 11.5.2 (Big Sur) which worked fine since I've had it. The machine only gets used every several months, since it's a dedicated dev machine for a specific software product that requires a very specific dev environment. The machine is clean, with only dev tools like XCode and some productivity tools like LibreOffice installed.
After the previous several month layoff, the machine suddenly failed to register either left or right clicks or taps on the trackpad. The trackpad itself gives very little feeling of travel, but the System Prefs are set up for "tap to click," so there shouldn't be any issue there. Mouse movement has never been affected, and works fine.
Plugging in a USB mouse still give me with the ability to left click, but strangely, I could right click with no problems using the mouse.
Now for the strange part: while messing about with the machine, I noticed that the trackpad responded to left clicks for roughly 30 seconds following reboot before returning to a non-responsive state. This seems to rule out hardware issues. That 30 second window was just long enough to pull up Mouse Prefs and make right mouse the primary button, so the machine is usable as long as I stick with a USB mouse, but this solution is non-ideal.
I'm loathe to spend money diagnosing and fixing a problem that could potentially cost me as much as machine is worth, so any help identifying the issue and a free or cheap potential fix would be appreciated.
