Crackling/Popping and lagged sounds

I can hear some crackling/popping sounds both on my login screen and in-game. Also, especially when I login in game, in the first 30 seconds, the music will be laggy (repeating sounds), and the image will stutter for some seconds.

I've tried disabling/deleting all addons, WTF folder, etc. Nothing solved.

Go to your Windows sound settings, select the sound device(s), go to properties and choose Advanved Settings. Set default frequency (or something like that) to 48000 Hz (DVD quality). Should fix it.