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Fixed in 2021.3.36f1, 2022.3.21f1



Found in



Issue ID




FSBTool ERROR: When opening a project containing audio files(.mp3), some importing of AudioClip may fail.



{*}How to reproduce{*}:

1. [Download this test project of Shinai|]
2. Open the project.
3. Check the following files
these files will be failed for import.
"Reimport" will also be failed.
*Expected results:* No errors are thrown

*Actual results:* "FSBTool ERROR: Internal error from FMOD sub-system." error is thrown and the audio files are not usable in the Editor.

The error is like:
Errors during import of AudioClip Assets/Other/Footstep02.mp3:
FSBTool ERROR: Internal error from FMOD sub-system.
FSBTool ERROR: Internal error from FMOD sub-system.
(Filename: C:\build\output\unity\unity\Modules\AssetPipelineEditor\Public\AudioImporter.cpp Line: 1062)
*Reproducible with:* 2021.3.34f1, 2022.3.17f1

*Not reproducible with:* 2023.2.4f1, 2023.3.0b1

Tested on Windows11.
The Error looks similar to UUM-8637.

We suspect that the fix for UUM-32863 *may be the cause of this issue.*


  1. Resolution Note (fix version 2022.3.21f1):

    Fixed backport of a MPEG codec bug resolution

  2. Resolution Note (fix version 2021.3.36f1):

    Fixed backport of a MPEG codec bug resolution

Comments (2)

  1. unity_mm-EFWU716_uIQ

    Feb 06, 2024 03:43

    I solved it by importing and copying the FSBTool folder from another Unity version (ex: 2021.3.27f1) and deleting the library folder.

  2. ScottyDSB

    Jan 25, 2024 18:30

    Started to happen with 2022.3.17 and also 3.18, some mp3 files that were working perfectly started to create errors when importing. Those mp3 files don't have any problem and can be heard with any mp3 player.

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