What?
http://steamcommunity.com/app/4000/discussions/1/648816742798726113
It happened to me :<.Coherently I uninstalled gmod, installed 2 antivirus softwares (bitdefender and malwarebytes).I am also changing my Steam password on a different computer.
people's steam wallets are being flushed so you might want to remove any saved payment info if you havent already
It's just happening to people who played the game and not those who haven't at all and/or got messaged "cough", right?
is it alright if you play single playerbecause i play it all the time, i cant join servers because my internet is a potato
Apparently fixed now.