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Fixed in 2021.3.28f1, 2022.2.18f1, 2023.1.0b12, 2023.2.0a7



Found in



Issue ID




[Being Backported] AssetBundle.LoadFromFileAsync causes errors when bundles are built using DisableWriteTypeTree [Document/add error message]



How to reproduce:
1. Open the user’s attached project
2. Open scene Scenes/SampleScene
3. Go to Tools -> Build Asset Bundles
4. Press the Play button and go to the Game view
5. Press the “Button” and observe the Console

Expected result: no errors are thrown
Actual result: errors are thrown: “Assertion failed on expression: ‘CurrentThread::IsMainThread()’“, “ObjectCreationLock(Write) must be taken and only on main thread”

Reproducible with: 2019.4.38f1, 2020.3.33f1, 2021.2.3f1, 2022.1.0f1, 2022.2.0a11

Notes: sometimes the Editor freezes

  1. Resolution Note (fix version 2023.2.0a7):

    Added error message when loading bundle without typetrees in the Editor

Comments (3)

  1. Alan-Liu

    Jun 06, 2022 04:10

    The Unity developer replied that they won't fix this issue, because "Bundles built without type trees are incompatible with the Editor and cannot be loaded in the Editor".

  2. Alan-Liu

    Jun 06, 2022 04:07


    I got this issue only in Editor. In built player(Android and iOS), it works correctly. If you only get issue with one specific asset bundle, maybe it's a different issue.

  3. naor_unity

    May 28, 2022 05:13

    Also getting this same issue with one specific asset bundles in Unity 2021.218f1

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