Bug in Black Mesa: involuntary shooting - ruining game

Hi, just joined this forum so my apologies if this has been covered already - I did a quick search but couldn’t find anything.

Anyway, I’ve found that BM has a very serious bug which is that, at apparently totally random intervals, my weapon will start to fire without me clicking the mouse. This is really annoying as it can alert enemies to me if I’m trying to sneak past them and of course wastes ammunition. I’ve made it to Xen so far, and am mainly staying on the crowbar or hive hand in order not to have to keep reloading to save ammo, which is very annoying although I can live with it. However, I’ve now come to the part where you have to navigate a room that’s been booby-trapped with exploding plants, and even a few hornets from the hive hand or a careless swing from the crowbar is enough to set them off and kill me.

Has anyone else experienced this? On the Steam forums I saw someone had suggesting verifying the integrity of the game files, which I’ve done but to no avail.

This problem happens when I used either of my mice, doesn’t happen in any other game and I’ve even seen it continue to happen after I’ve unplugged the mouse, so I’m pretty sure it’s a problem with the game itself.


Tap the mouse and it will stop firing, or change weapons.


yeah I’ve seen that advice elsewhere - tried it, no dice.

If it’s fixed the problem for other players but not for me, that suggests that the bug might have more than one root cause.