Zipped archives of games need to be downloaded again?

[daminshi]

I have a spare hard drive with a huge amount of Steam games on them. Today, I saw a game had been updated and thought just to unzip the game from my hard drive onto Steam, give it the update, and zip it back to my archive. The problem is, even if I put the game in the right place and do a Install or Verify Integrity Cache, Steam sees the pre-existing files and for some reason decides to redownload the entire game again. Why is Steam forcing me to redownload games I already have downloaded when I click the Install button? That doesn't make any sense, it wastes my bandwidth, and my time.

[Washell]

You need to zip the .acf files in \steamapps too, or just use the built-in back up system from Steam.

[Ogami]

That can happen if you manually archive a game. Either use the build in archive function of Steam to create your backups, or if you just zip the game folder make sure that you include the app manifest that belongs to the game. That file tells Steam that the game is installed.
Without the manifest you can run into the problem you just described, Steam trying to redownload the whole game.

[daminshi]

Is there a way to get the acf file without downloading the whole game again? And can I just dump all these acf files into the /steamapps folder without Steam bugging out?

None of my archives have those files and these JSON files are always using their SteamAppID's so they're hard to keep track. And the reason why I don't use Steams archive tool is because it broke quite a bit the last time I even tried to use it. It's wholly unreliable.

[Ogami]

No. the steam app manifest is different for each user since it contains your system information and that the game is installed on your specific system. There is no way to get the appmanifest without redownloading the game im afraid. Mind you, for most games Steam should detect the files when you choose reinstall and not redownload everything. Its about 5-10% of games in my experience that need a complete redownload. Most will just download a few files and then show as installed.

For future archving just google the app manifest number for the game you want to save and include that appmanifest into the zip. I would not recommend just dropping all the appmanifest into the steam order since then tons of games will show as installed and Steam will start downloading all those titles if it cant find the data.