All Steam game servers now use SteamCMD to download and update game server files. HLDSUpdateTool has been retired and will no longer function.
For more information on installing and using SteamCMD, please see the Valve Developer Wiki which includes the latest information on SteamCMD.
For a list of dedicated servers and games that SteamCMD supports on Steam, please see the Dedicated Servers List.
Please join the dedicated server discussions list for your operating system and review the mailing list archives to find solutions to Valve dedicated server issues or to post a question to the appropriate list:
You can also post questions and search for help in Steam Discussions.
Steam Support does not provide support for mods or game servers. Please use the above resources for assistance with game servers on Steam.