Subnautica: Below Zero

Take a backup of the file before you begin!

If you mess up you can always delete the file and it will be re-created when you start the game, but all the settings in it are lost.

The sensitivity for this game is in the file C:\Program Files (x86)\Steam\SteamApps\common\SubnauticaZero\options.bin (default location). This is not a regular text file, but a file in HEX format.

To edit the sensitivity in HEX format, you first need a HEX editor.

Notepad++ (version 6.8.X, not out for 7 yet) has a HEX editor plugin that's free, and a paid option is UltraEdit.

To install the plugin in Notepad++, go to Plugins -> Plugin Manger -> Show Plugin Manger, scroll down to "Hex-Editor", check the box and click install.

Once installed, open the file, and press Ctrl-Alt-Shift-H to switch to HEX mode.

If you're unfamiliar with the hexadecimal system, it goes 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f. Uppercase or lowercase letters are irrelevant, they have the same value.

UltraEdit will show the cursor position in HEX format, but Notepad++ will not, it will show the line and column.

The position of the sensitivity might change, but it always comes one space after "Input/MouseSensitivity".

In UltraEdit, the position for the sensitivity in this example is byte 1d, 1e, 1f and 20:

In Notepad++ you can see the line number in HEX on the left, but not the position in HEX. So the sensitivity is in this example on line 2 column 14, 15, 16 and line 3 column 1: