Find out where Steam is installed, and write it down. It's usually C:\Program Files (x86)\Steam or C:\Program Files\Steam. I have it installed in C:\Steam Invalid Steam UserID Ticket Exit Steam Go to C:\Program Files (x86)\Steam and delete ClientRegistry.blob Go to C:\Program Files (x86)\Steam\config and delete everything in that directory No servers found or cannot connect to Master Game Server Exit Steam Go to C:\Program Files (x86)\Steam\userdata\\config Rename localconfig.vdf to localconfig.vdf.bak Failed to find Steam Exit Steam Press Windows key and Pause Break at the same time Click on Advanced System Settings Go to the Advanced tab, then click on Environment Variables Look for the entry PATH in the System variables section, select it and click on Edit In the Variable value field, add a semicolon and the directory of Steam at the end of the field. DO NOT REMOVE ANYTHING. Press the End key on your keyboard to make sure you're at the end of the field. Unlocalized or language pack missing Go to your Library Right click on the game, click on Properties Select another language than English (German, Spanish, Japanese, etc.) Wait for Steam to fully download shit Start the game for a minute, then close it Switch it back to English Hard Drive filled with shit I don't need Use Codeusa SteamCleaner to get rid of them packages like DirectX, PhysX, .NET Framework, etc. that you only install once, and then don't need anymore (you probably installed them a million times anyway). Still clogged? Try Bleachbit. It will get rid of even more redundant crap. Gaming session exceeds 48 hours