Steam error

[DeAdLy_cOoKiE]

When I try to run HL2 I get this error:
"This operation cannot be completed when Steam is in offline mode."

Deathmatch still works but how can I get HL2 to run?

 

[ríomhaire]

You have to finish downloading the patch you started downloading. then play it while online for a few minutes.

 

[DeAdLy_cOoKiE]

what patch?