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Fixed in 2020.3.38f1, 2021.3.9f1, 2022.1.12f1, 2022.2.0b2, 2023.1.0a1



Found in




Issue ID




[IL2CPP] Player hangs for 20 seconds after closing it when running threads



Reproduction steps:
1. Open the user's attached "" project
2. Go to Edit > Project Settings > Player > Other Settings > Configuration and make sure IL2CPP is set as Scripting Backend
3. Build and Run for PC, Mac & Linux Standalone
4. After the project is built and the Player opens, close it

Expected result: Player closes instantly
Actual result: Player hangs and closes after 20 seconds

Reproducible with: 2021.1.0a8, 2021.3.3f1, 2022.1.1f1, 2022.2.0a14
Not reproducible with: 2019.4.39f1, 2020.3.34f1, 2021.1.0a7

Not reproducible with: Mono Scripting Backend

Tested and reproduced with: Windows 10

  1. Resolution Note (fix version 2020.3.38f1):

    In 2020.3 the player didn't hang for 20 seconds, but has the same underlying issue. The issue is that IL2CPP leaks an internal thread object each time a thread is created. The shutdown code in 2021.2+ caused these leaked thread objects to slow the player close.

    So this fix only cleans up that memory leak (which is relatively small).

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