To force Steam into offline mode, you can disable your network connection.If your laptop has a hardware switch for Wi-Fi, disable it.When you’re ready to go offline, click the Steam menu and select Go Offline.Click the Restart in Offline Mode button and Steam will restart in offline mode – features like Steam’s server browser, friends, and achievements aren’t available offline.Steam will launch in offline mode each time you use it until you manually re-enable online mode.If you’re performed these steps, Steam’s offline mode should now work without any problems until the next time you tell Steam to go online.I'm temporally on super slow broadband at my parents and want to play a game I got now, not in 10hours :-/ Thanks Answer would be - it depends.
If Steam’s offline mode isn’t working at all, you may still be in luck – some Steam games don’t use Steam’s DRM at all and can be launched manually.
I know there are already questions like this, but there are no decent answers that I can comprehend. It's not a duplicate of the other question because that's not my problem. He has possible connection to the Internet, I don't. You cannot login to Steam with a username and password without an Internet connection.
You cannot save credentials without first logging into Steam with a user name and password.
If you have an Ethernet cable plugged into your computer, unplug it.
You can also disable the adapter completely in Windows. Right-click the network adapter in use and select Disable to disable it. Launch Steam and, instead of attempting to contact the Steam servers for a period of time and failing, it should immediately notice that the network connection is unavailable. These steps won’t help if games aren’t fully updated or there’s an update for Steam available.