I don't know much about it, but I think it's better you re-download it, by steam now.

the torrent files are not exaclty the same as the steam game, torrents usually come with crack for example and are usually few versions behind the original, you could try copying it to that location and do a filecheck, no idea if it will actually work but i'd give it a shot.

If i'm right,you can't copy,you WILL need to re-download the 15gb files. /// BTW,thx for the giveaway

You can't. Steam and torrent are not compatible. You cant play Steam games without Steam. Torrent files are modified to make them DRM-Free and Steam won't recognize them in any case. I once tried to copy a game manually from my Steam Library folder to a USB so my brother could play it on his PC, but it didn't work, so how could a torrent?

Steam does not delete the files it copies them to Steam/SteamApps/downloading/XXXXXX.
It will only leave wrong files in Steam/SteamApps/common/XXXXXX, i deleted them while downloading the new files.
Also sometimes Steam shows that it needs to download the whole game but you will notice the progress bar will fill itself very fast.
Just let Steam do its job.
Confirmed working but buggy: TombRaider, SleepingDogs, Hitman Absolution, HotlineMiami, Serious Sam:BFE..... etc.

Re-download it

You may have more errors if you change some files

Well, you can put the files in the steam folder and then make a "verify game files", the major bad thing is that you need to put the exactly folder name for the game (you cant call it Counter_strike_go, yo need to call it Counter Strike: Global Offensive), my idea, start the download in steam of you game, at least 10mb or a bit more, then close steam, then go to the steam folder, your account, common and find the game folder and the paste the files of your torrent there, but be carefull, overwrite the folder with the same name and in the same ubication (example, bin32 overwrite with the same bin32 in the torrent AND in the same folder), the start steam again and let him download the remain (if exist), then make a varify and done.
I hope this help you, that work for me with for GTA:VC and Hitman: Blood Money, good luck.

dude, u r doing it right. after copying files, start install. it'll show it needs to download whole game. now restart steam, and you will will have very less to download.

It will cause a conflict with the .acf files. I tried this before. Might be possible with certain games.

i'm usually starting steam download, after some time stop, copy over old files, and verify integrity. works every time. still will download something tho, non-steam files are still bit different

It depends if the files you downloaded from the torrent were already cracked, ie the installer has been completely modified or if there's a "crack" directory you have to copy and paste in the game's install directory.
In the 1st case you have to redownload
In the 2nd case, just don't copy the "crack" folder and try to recover the game through Steam

Hope it helps

I don't think you can. Torrents have different files/structure from Steam ones so you'll just have to redownload :-(

Thank you for the suggestion, everyone! The problem is solved now. 1 GB left to download but hey, that's 15 times better than downloading 15 GB, isn't it? I'll close this topic when the GA ends.

Cool, I had tried this with a game that was super non-loss-illy compressed in torrent (but steam wanted a 5 gig download), but never could figure out how to get steam to recognize the files. It is great to hear you can get it to work.