unity build_error ai_generated true

IL2CPP error: Managed/UnityEngine.dll is not available for codegen. This can happen if the IL2CPP backend is missing or corrupted.

ID: unity/il2cpp-codegen-managed-backend-unavailable

Also available as: JSON · Markdown · 中文
82%Fix Rate
88%Confidence
1Evidence
2023-06-15First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Unity 2021.3.0f1 active — — —
Unity 2022.3.0f1 active — — —
Unity 2023.2.0f1 active — — —
Unity 2024.1.0b1 active — — —

Root Cause

The IL2CPP code generation backend cannot locate the managed UnityEngine.dll, often due to incomplete installation or corruption of Unity's IL2CPP support package.

generic

中文

IL2CPP 代码生成后端无法找到托管的 UnityEngine.dll，通常是由于 Unity 的 IL2CPP 支持包安装不完整或损坏。

Official Documentation

https://docs.unity3d.com/2023.2/Documentation/Manual/IL2CPP.html

Workarounds

  1. 85% success Reinstall the IL2CPP package via Unity Hub: Open Unity Hub, select the project's Unity version, click 'Manage Modules', ensure 'Windows Build Support (IL2CPP)' or equivalent is checked, then apply changes. 
    Reinstall the IL2CPP package via Unity Hub: Open Unity Hub, select the project's Unity version, click 'Manage Modules', ensure 'Windows Build Support (IL2CPP)' or equivalent is checked, then apply changes.
  2. 90% success Manually repair Unity installation by running the Unity installer's repair option: Uninstall Unity version via Control Panel, then reinstall from Unity Hub with IL2CPP support included. 
    Manually repair Unity installation by running the Unity installer's repair option: Uninstall Unity version via Control Panel, then reinstall from Unity Hub with IL2CPP support included.

中文步骤

  1. Reinstall the IL2CPP package via Unity Hub: Open Unity Hub, select the project's Unity version, click 'Manage Modules', ensure 'Windows Build Support (IL2CPP)' or equivalent is checked, then apply changes.
  2. Manually repair Unity installation by running the Unity installer's repair option: Uninstall Unity version via Control Panel, then reinstall from Unity Hub with IL2CPP support included.

Dead Ends

Common approaches that don't work:

  1. Reimport all assets via Assets -> Reimport All 95% fail

    Reimporting assets does not repair the IL2CPP backend installation; it only refreshes asset metadata.

  2. Delete Library folder and restart Unity 80% fail

    Deleting Library removes cached data but does not fix missing IL2CPP components in the Unity installation.

  3. Switch to Mono scripting backend and back to IL2CPP 70% fail

    This may trigger a rebuild but does not address underlying corruption of the IL2CPP package.