I had this happen to me on Steam for Windows as well, so it might be one of those "features".. I suspected the installation was somehow corrupt, so I performed verifications and all the other stuff that the Valve support suggested. I am on a 3G modem for all my Internet connectivity, so I do not really like to spend several hours downloading. The cynic in my suggests that the BASE game installation is 4.7 Gb, and then all the rest is all these stupid add ons (hats, "Texas Buttcheek Fish Slapper Spanner" etc.) that only serves to detract from the gamign experience. For every minute I spend fixing these issues I feel more like a product than a customer..
Sounds like the Steam client bases its install sizes on what was manually entered into their system way back when the game was new, rather than the actual size of the install package. That's a pretty serious issue, considering how many of their games have had sizable content patches since they were released. Likewise, the system requirements in the store should be set up to automatically change to match the size of the install package.
I can't repro this. When I go to install TF2 is says that 10958 MB will be required.
Note also the initial number is a disk space estimate and so won't directly equal the download byte count as things can be compressed for downloading.
I've just noticed that I previously installed Team Fortress 2 Beta. So I removed it and now installed regular (non-beta) version. It claims to install 7304MB, but when downloading started, it needs to download 12.2GB.
One more thing I noticed, right after the downloading started, it started on 2.6GB. Is this correct behavior (e.g. some shared files with CS:S possibly)? Either way, it's confusing for user.
I don't have CS:S, but I do know that it shares an engine with TF2, so all the files named "source 2007 *.gcf" are probably common to them. But those only come to a total of 1.37 GB, so I'm not sure what would account for the rest.
It's possible downloads would start at a non-zero number if there is shared content. That's all part of an older content system which we're moving away from, so this will improve over time.
Closing as this appears to have naturally resolved itself with the transition to steampipe.
Nothing extracted yet.
The dialog before install contains an information that 4773MB will be required. However when download starts, it's actually downloading 12.2GB.
System info