Do yourself a favour: In the steam client: Right click Skyrim->properties->Update Options->"Do not update automatically".
Then press Alt-F4 while in this window.
Actually no. "Do Not Update Automatically" only really applies to games you are
not playing. As soon as you try to launch a game while in online mode it will try to update it if one is available. The intent of this feature is so games you don't play currently (or maybe never again) don't simply update & waste your bandwidth. For some it might be preferable that this happens, so next time they do play said game it's ready to go.
I usually sit in Offline mode until *I* chose to update something. It's easy for me as I only have two Steam titles and a couple of demos. Those with a larger collection can benefit from "do not update automatically" in the following way...
. Assuming you're in offline mode
. Set do not update automatically for Skyrim
. Go online and let your other title(s) update automatically
. Do NOT run Skyrim at this stage, it won't update.
. Pop back into offline mode
. Play your update game
. Play your NOT updated Skyrim
. You will likely need to set "Do not update automatically" once more if you go online again.
This is basically what I did when I needed to update one title but not Skyrim.
Cheers,
Scoob.