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Fixed in 2021.3.31f1



Found in


Issue ID




Crash in audiomixerruntime.cpp when loading AudioMixer assetbundles built prior to 2021



Open the repro project and play SampleScene to potentially reproduce. Also try a standalone player. The repro loads a scene bundle built in 2019 which contains an audio source and mixer with filters. The repro is not 100% reliable as it depends on uninitialized memory to crash.
* Try using a locally produced build of the Editor.


The issue is that AudioMixerConstant::groupConnectionCount was added in [] but was not default initialized. If the loaded asset doesn't contain this it may end up with an undefined value. 

You can force reproduce the crash by default-initializing groupConnectionCount to a high value to mock-up possible memory state.

  1. Resolution Note (fix version 2021.3.31f1):

    Added default initialisation of a member variable that would be garbled when loading asset bundles that were created before the variable was introduced, causing a crash from illegal memory access.

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