When you login to your Steam account by default it will sign-in to the Friends chat menu, if you do not want this to happen, it is simple to change. This quick guide will show you how.
If at any point you decide that you want to re-enable this settings, simply follow the above steps, and then check Sign in to friends when Steam Client Starts
There is an alternative option for if you just want to play games offline (without your friends seeing), or don't want to download new updates. You can enable the Offline Mode.The Offline mode is quite convenient if you focus on single player games. Once enabled you can seamlessly launch your games without having to connect to the Steam network each time.
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