how can i fix it.thank you in advance.

[mstdigg]

Running on 64 bit Windows with 8 GB RAM 
Version: v1.12.14 (Stable)01.05.2020 13:31:24: Critical error occurred
System.MissingMethodException: Метод не найден: "Void System.Runtime.GCSettings.set_LargeObjectHeapCompactionMode(System.Runtime.GCLargeObjectHeapCompactionMode)".
   в _lea77K0CnqI7LBCxN73MjjdbPaJ._RT1lBvzfhVzcDZ6jmYewDTkUdvx(Single , Int64 , Boolean )
   в _s54YxMQ8l5DBeihbmw81nJkPTSU._RT1lBvzfhVzcDZ6jmYewDTkUdvx(Single )
   в _s54YxMQ8l5DBeihbmw81nJkPTSU._EZIJU8BLizIQdIOGgxu5BrkHzpV(Single )
   в Vintagestory.Client.NoObf.ClientPlatformWindows.window_RenderFrame(Object sender, FrameEventArgs e)
   в System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   в OpenTK.GameWindow.RaiseRenderFrame(Double elapsed, Double& timestamp)
   в OpenTK.GameWindow.DispatchRenderFrame()
   в OpenTK.GameWindow.Run(Double updates_per_second, Double frames_per_second)
   в _gilSYm6aSzOct8TKUm64HAM8OHp._tyidesQGCE1oKHv8YEo8HwYCSty(_RxGTCHor7fqeGRNMEH5pZVfBHHK , String[] )
   в _xmrDk9pogtvR6xvbzmBc2dtFsbu._tyidesQGCE1oKHv8YEo8HwYCSty(ThreadStart )
-------------------------------
 

[mstdigg]

it appears at startup

 

[Tyron]

Download a newer version of the .net framework to fix this, e.g. https://dotnet.microsoft.com/download/dotnet-framework/net472