Backup game - how does it work? Or why doesn't it work?

[Humboldt Squid]

On thing I noticed recently is, that when I backup a game manually not all files needed for playing the game are actually stored in the backup folder.
This is rather unfortunate, because when I restore the game, Steam stars downloading huge portions of the up to date game anyway.
Why?

In this context - why does Steam use my computer as a download source for family computers without asking me? This is an extremly annoying behavoiur as it dramatically slows down the network speed of my computer so I can't work properly any more.
Is there a way to prevent this intrusive and annoying behaviour?

[Ogami]

What do you mean "backup manually" ?
Do you just make a copy of the game files folder and store it somewhere?
Then later copy it back, Steam tries discovering the files and redownloads parts/all of it?
Thats because you also need to copy over the correct appmanifest file for the game.
In the steamapps folder are bunch of files in the format appmanifest_XXXXXX.acf with X being different numbers.
Each game has such a file, it tells Steam the game is installed and if all files are present.
Without that file Steam usually cant locate all the files and will redownload huge chunks of a backup game.
So search for the correct appmanifest number for the game you want to backup (google it or look at the number in the address bar of your browser for the store page of the game, thats the appmanifest number of it too) and make a copy of that file.
Then when you want to restore the game copy over the appmanifest file to the steamapps folder and the game files to their location and restart Steam.
The game will be shown as fully installed and ready to play.
Bar any patches and updates that released in the meantime of course.


As for your second question, i dont really know what you mean with "why does Steam use my computer as a download source for family computers" ?
Could you explain a bit more?

[Kargor]

I wasn't aware that Steam has implemented a "download from other computers on the same network if possible" by now -- good for them :-) That has always been something I would have suggested they do if someone is bored.

[Satoru]

Originally posted by Karl Martell:

On thing I noticed recently is, that when I backup a game manually?

And that's why it doesn't work

https://help.steampowered.com/en/faqs/view/4593-5CB7-DC3C-64F0

Use Steam to backup and restore games

If you do anything else, it will not work

[Satoru]

Originally posted by Kargor:

I wasn't aware that Steam has implemented a "download from other computers on the same network if possible" by now -- good for them :-) That has always been something I would have suggested they do if someone is bored.

You can read more about the feature here

https://help.steampowered.com/en/faqs/view/46BD-6BA8-B012-CE43

[Ogami]

Originally posted by Satoru:

Use Steam to backup and restore games

If you do anything else, it will not work

Well, no, thats also not correct. You can just copy over the installation folder no problem as a backup, as long as you remember to also copy the correct appmanifest file for the game too.
I backed up my Steam games like that for years and never had a problem with that method.
I actually recommend against the Steam backup function because its incredible slow and often bugs out when reinstalling the games from the compressed archive it creates.
Manual copy + appmanifest is the most sure method in my opinion.

[Humboldt Squid]

Originally posted by Satoru:

Originally posted by Karl Martell:

On thing I noticed recently is, that when I backup a game manually?

Use Steam to backup and restore games

Well, I use Steam's backup system (Backup and restore games). That is the whole point. If I remember correctly it used to work like this: You backup a game, you restore it from the local files and you were ready to go.
Now only a fraction of the game (e.g. HL2) is backuped and upon restoring the game Steam starts to download tons of data. Why?