Vanilla Proton 9.0-3 runs this game out of the box with little to no issues. However, follow the steps below for the optimal experience.

NewDark/T2Fix

In order to get the best experience, you need NewDark, which is THE way to play Thief and Thief II these days. You can easily get NewDark together with other fixes via the T2Fix package. Get the "with mods" version, as it has a couple of extra fixes.

• Release thread HERE
• Github HERE

If you don't have ProtonTricks and Wine already installed, you can easily run the installer with the following command:

$ STEAM_COMPAT_CLIENT_INSTALL_PATH="$HOME/.local/share/Steam" STEAM_COMPAT_DATA_PATH=~/.local/share/Steam/steamapps/compatdata/211740 WINEPREFIX=~/.local/share/Steam/steamapps/compatdata/211740/pfx/  ~/.local/share/Steam/steamapps/common/Proton\ 9.0\ \(Beta\)/proton run ~/Downloads/T2Fix_1.27e_with_mods.exe

Point the installer to the following path: Z:\home\<$USER>\.local\share\Steam\steamapps\common\thief_2.

Next, select the following components to install:

1. Common Script Modules
2. Mods: Thief2 Fixed
3. Mods: T2FMDML

On the next screen you should set the preset to "High", and you could also opt to install OpenAL Soft if you want (more on that later).

That's all you need. These are fixes only. Personally I would highly discourage you from installing anything else, including texture packs, HD mods, etc.

Fan Missions

For Fan Missions, I recommend you just stay with the default missions selector, fmsel. It comes out of the box and works mostly fine.

Here's my recommend setup. Create the following directory structure in ~/Games/:

T1FMs
├── Archive
└── Installed
T2FMs
├── Archive
└── Installed

Then, edit cam_mod.ini in the Thief 2 installation directory. Change the line with fmpath to

fm_path Z:\home\<$USER>\Games\T2FMs\Installed

Now, in Steam, set the launch options to

%command% -fm

The first time you run the game like this, fmsel will ask you if you want to pick an archive path. Say yes, and set it to Z:\home\<$USER>\Games\T2FMs\Archive.

You can now put all your FM archive files into the Archive directory, and fmsel will pick them up. You can rightclick and pick Install to set up the FM in the Installed directory.