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Fixed in 5.1.0



Found in


Issue ID




4.5+ shader compiler hangs on windows when entering play mode



Closed: Number of fixes for shader compiler were added in Unity 5 cycle. User doesn't experience it anymore in 5.1.

UnityShaderCompiler.exe has zero CPU activity, but pressing Play in editor just seemingly hangs, until the compiler process is killed.

Nothing much useful in editor log, waiting for more info.

Problem did not happen in 4.3.x.

Comments (7)

  1. Aras

    Aug 31, 2015 11:58

    Just the fact that there are UnityShaderCompiler.exe processes doing nothing does not mean it actually hangs there (Unity does spawn multiple compiler processes, and then they sit around waiting for shader compilation to do). My thinking is that the actual "hang" is somewhere completely else. We could never reproduce the actual "shader compilation hangs" problem here :/

  2. deepesh

    Jan 21, 2015 08:06

    Temp Solution:
    Try ending task for mono.exe from background process from Task Manager.

  3. comatic

    Oct 30, 2014 12:45

    In our project we have a very similar problem, I suppose, of the same origin. Since we migrated to Unity 4.5.5f1, the editor freezes after building the project, whichever the platform is selected, both in graphical and in batch mode. UnityShaderCompiler.exe is hanging in memory, neither it nor the editor consuming CPU time.
    This breaks our build process as -quit flag does not work now.
    Reproduced on multiple machines.

  4. mateiasu

    Oct 06, 2014 16:58

    We encounter a similar issue with a headless Windows build agent, that hangs while building because the UnityShaderCompiler.exe doesn't stop.

  5. chris_durel

    Sep 05, 2014 21:02

    Just want to add that I have the same problem as DRSNOW. Finally figured out what was holding on to my ports. For whatever reason, UnityShaderCompiler.exe is hanging, and subsequently not releasing any ports with my network game. Can be fixed by me just killing the process each time, but it's very annoying.

  6. ahrakos

    Aug 21, 2014 12:09

    I got a SocketException from my internal webserver (port 8080) when the shader compiler exe is running.

    System.Net.Sockets.Socket.Bind (System.Net.EndPoint local_end)
    System.Net.EndPointListener..ctor (System.Net.IPAddress addr, Int32 port, Boolean secure)
    System.Net.EndPointManager.GetEPListener (System.Net.IPAddress addr, Int32 port, System.Net.HttpListener listener, Boolean secure)
    System.Net.EndPointManager.AddPrefixInternal (System.String p, System.Net.HttpListener listener)
    System.Net.EndPointManager.AddListener (System.Net.HttpListener listener)

  7. DrSnow

    Aug 06, 2014 16:16

    I have this problem too, it for some reason prevents closing of open ports when stopping the game by pressing play in editor. Then I get the "port already in use"-error every time I try to start again. It is solved by killing the process and does not reappear until unity is restarted.

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