Citrix (https://www.citrix.com/) Workspace client has effects on games built using older versions of the Unity game engine. As a result, games crash, games don't start etc and it's sadly not something we can sort. Of our games this affects Cities Skylines and BattleTech.
To identify if it's Citrix causing issues when your game crashes open the Output log (or crash log) and look at the amazing wall of text. If you see the following around the top of the log it's Citrix:
Initialize engine version: 5.6.6f2 (6bac21139588)
> GfxDevice: creating device client; threaded=1
> SymInit: Symbol-SearchPath: ’.;C:\Program Files (x86)\Steam\steamapps\common\Cities_Skylines;C:\Program Files (x86)\Steam\steamapps\common\Cities_Skylines;C:\Windows;C:\Windows\system32;SRV*C:\websymbols*http://msdl.microsoft.com/download/symbols;', symOptions: 530, UserName: ‘<your username>’
There is a workaround and that is to install Citrix the following way:
1. Uninstall Citrix Workspace
2. Re-Install it from Command Prompt using the following command:
Alternatively you can use the edition of Citrix Workspace in the Windows 10 Store, which lacks the feature that causes this problem to older Unity games.