So up until about a week ago when I brought my computer downstairs (where there's internet), I had no problem running CounterStrike: Source offline. I brought it downstairs and Steam worked great - I could play all of my games and I installed Portal, as I needed internet to do that. Now I brought it back upstairs again, with no internet, and I can't play anything.
The operation cannot be completed while in offline mode
...is the error it gives me. So I can't play any games. Not even Portal, which isn't even an online game.
I'm guessing it was some sort of Steam update or something. Anyways, it's bugging the heck out of me, and that means I may not even be able to play LAN CS:S with my friends when they come over.
Any ideas?