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Fixed in 2021.2.X

Fixed in 2019.4.X, 2020.3.X, 2021.1.X



Found in






Issue ID




Crash on PAL_LocalIPC_IsConnected when IPC fails on launch

Shader System


How to reproduce:
1. Open the project attached by the user from ""

Expected result: When IPC fails to connect, should fall back to sockets
Actual result: Editor crashes

Reproducible with: 2019.4.20f1, 2020.2.2f1, 2021.1.0a6, 2021.2.0a7
Not reproducible with: 2018.4.32f1, 2019.4.19f1, 2020.2.1f1, 2021.1.0a5

1. Majority of cases come from China, although there are exceptions

First lines of stack trace:
0x00007FF628AFB825 (Unity) PAL_LocalIPC_IsConnected
0x00007FF6288F15A2 (Unity) GetShaderCompilerPerThreadInternal
0x00007FF6288FD474 (Unity) ShaderCompilerSupportsRequirements
0x00007FF629F33652 (Unity) GetSerializedSubProgramForShaderSnippet
0x00007FF627F0A942 (Unity) CompileSingleVariantJob
0x00007FF627F0A678 (Unity) CommitVariantCompileJob

  1. Resolution Note (fix version 2021.2):

    Fixed in 2021.2.0a10, now instead of crashing, the Editor will have a popup indicating the users that there was a problem during installation, no file access, or antivirus blocking files.

  2. Resolution Note (fix version 2021.1):

    Fixed in 2021.1.1f1

  3. Resolution Note (fix version 2020.3):

    Fixed in 2020.3.2f1

  4. Resolution Note (fix version 2019.4):

    Fixed in 2019.4.23f1

Comments (1)

  1. AaronZurawski

    Mar 12, 2021 19:57

    This can also happen if you're running Unity under a service on a CPU with a large amount of cores, as is commonplace in CI/CD.

    We were able to resolve this issue by increasing the amount of non-interactive sessions allowed by windows as explained here:

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