Weird Camera Shutter Sound when Clicking S

[Voltz]

Whenever I click "S" it makes a shutter sound and deactivates my A so I cant run sideways... help?

Its even in the menu, not just ingame.

 

[Ciaran]

Using any external software on your game? If not then try going into your controls and seeing if the S key appears red on the 'Move Backwards' key (Or Similar).

 

[Mycaelis]

The only shutter noise I can think of quickly is Steam Screenshots.

What's you steam screenshot key set to? Something on the letter S maybe?