A lot of Unity-based games exhibit spurious errors that can be traced down to the
mono.dll binary. There are various crashes, one of the most famous being something about
GetThreadContext Failed or similar.
To fix the game, you will have to download Unity (the free version is fine), install using the default options (pick 64 bits) and then browse to the installation folder (for x64, the installation directory will be by default at
You can use Windows search to locate
mono.dll in any sub-folder - the one you need is the one located under the
Editor\PlaybackEngines\windowsstandalonesupport\Variations\win32_nondevelopment_mono\Data directory. You could probably attempt the procedure with the
mono.dll under the
win64_nondevelopment_mono folder - but you most likely want the non-developement version (hence the folder name
nondevelopment) instead of the development version since it will include additional debugging information that will not be useful for playing your game.
The next step is to copy the
mono.dll from the Unity directory and overwrite the
mono.dll in your game folder directory. For instance, for the game Tyranny, distributed by Good old Games (GoG), the
mono.dll you have to overwrite with the one from Unity, is located inside the
C:\GOG Games\Tyranny\Tyranny_Data\Mono folder.
Games known to be affected by this issue are:
including many titles of the Good old Games (GoG) releases that are built using Unity and mono.