# Android/IOS error Could not load bank 'Master Bank' : ERR\_FORMAT : Unsupported file or audio format
**URL:** https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289
**Category:** Unity
**Tags:** unity
**Created:** [May 27, 2026, 1:06pm UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289 "2026-05-27T13:06:19Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [May 27, 2026, 1:06pm UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/1 "2026-05-27T13:06:19Z")
Help me, please.
I updated the FMOD in the project from 2.01.11 to 2.03.13.
I fixed all the bugs in the editor, but a problem appeared in the builds. The game does not start and the error “Could not load bank ‘Master Bank’ : ERR\_FORMAT : Unsupported file or audio format.” To load banks I use the Asset Bundles type. The FMOD studio version is also 2.03.13. All sounds in the editor work.
I reassembled the bundles, reassembled the banks, deleted Library, deleted FMODCahce. Nothing helps
Unity version 6000.0.64f1
---
### Author:  [@Connor\_FMOD](https://qa.fmod.com/u/Connor_FMOD)
#### Post date: [May 27, 2026, 11:28pm UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/2 "2026-05-27T23:28:54Z")
Hi,
With the following settings:
Could I grab the full player log? It can be shared here as a `.txt` or uploaded to your [profile](https://fmod.com/profile#uploads).
Would it be possible to compare the banks included in the build to those loaded by the editor to make sure they are the same? If possible could both set of assets be uploaded to your profile as well?
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### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [May 29, 2026, 10:34am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/3 "2026-05-29T10:34:17Z")
Hi,
thank you for your answer.
Here is a single message from logs about fmod (logcat):
2026.05.29 13:22:34.221 28213 28295 Error Unity [FMOD] System::loadBankMemory(0x7b201a3598, 21, 0, 0, 0x7c60bfa370) returned ERR\_FORMAT for STUDIO\_SYSTEM (0x1FFF1F).
2026.05.29 13:22:34.221 28213 28295 Error Unity FMODUnity.RuntimeManager:ERROR\_CALLBACK(IntPtr, SYSTEM\_CALLBACK\_TYPE, IntPtr, IntPtr, IntPtr)
2026.05.29 13:22:34.221 28213 28295 Error Unity FMOD.Studio.System:FMOD\_Studio\_System\_LoadBankMemory(IntPtr, IntPtr, Int32, LOAD\_MEMORY\_MODE, LOAD\_BANK\_FLAGS, IntPtr&)
2026.05.29 13:22:34.221 28213 28295 Error Unity FMODUnity.RuntimeManager:LoadBank(TextAsset, Boolean, String)
And I am attaching bank from project in profile.
Thank you.
---
### Author:  [@Connor\_FMOD](https://qa.fmod.com/u/Connor_FMOD)
#### Post date: [June 1, 2026, 6:48am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/4 "2026-06-01T06:48:41Z")
Thanks for the info and the bank.
Could we please test deleting all generated FMOD bank assets in the Unity project, when using `Asset Bundle` Load options these will be under the `FMODBanks` and the `StreamingAssets` directories.
Then rebuilding banks for PC and Android and regenerating all the `.byte` files that will be included in the build? It is possible that the Android assets were stale from the 2.1 version while the banks being loaded for the editor are using updated ones.
Would it be possible to share the script you use to generate the `AssetBundles` for your project?
We should also be seeing
```auto
[FMOD] FMOD_System_Create : Header version = 2.03.13. Current version = 2.03.13.
```
In the logs as well to confirm the FMOD version used by the integraion. We just need to make sure that we are making a development build and have the logging level set to `log`.
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### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [June 1, 2026, 8:26am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/5 "2026-06-01T08:26:07Z")
Thanks for the answer.
I deleted and regenerate all banks and .byte files before this 3 times.
The pipeline to create the AssetBandles:
=\> import/update banks to “Plugins\FMOD\Banks”
=\> Delete old .bytes files (optional)
=\> use “Refresh Banks”
=\> validate created .byte files and check Bundle paths
Here is screenshots with logs and settings, I hope thats help you
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### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [June 1, 2026, 8:26am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/6 "2026-06-01T08:26:40Z")
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### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [June 1, 2026, 8:27am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/7 "2026-06-01T08:27:23Z")
---
### Author:  [@Connor\_FMOD](https://qa.fmod.com/u/Connor_FMOD)
#### Post date: [June 2, 2026, 2:24am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/8 "2026-06-02T02:24:18Z")
Thank you for the images.
I see in your FMOD Integration settings you have the `Source Type` set as `Single Platform Build`. Could we test changing it to `Multi Platform build` and seeing if that updates the built banks?
Are you also doing `Clean Builds`?
We use the following to build the asset bundles from the bank bytes:
```csharp
public class BuildAssetBundles
{
[MenuItem("Tools/Build Asset Bundles")]
public static void StartProcess()
{
BuildTarget buildTarget = BuildTarget.Android;
EventManager.CopyToStreamingAssets(buildTarget);
BuildPipeline.BuildAssetBundles(Application.streamingAssetsPath, BuildAssetBundleOptions.None, buildTarget);
EventManager.UpdateBankStubAssets(buildTarget);
}
};
```
Could I see your script? It can be uploaded to your [profile](https://www.fmod.com/profile#uploads) too.
The editor logs look good, can we check if we are seeing the same on Android with logcat and share the full logs from starting the app?
How are you loading the banks? For example this is how I loaded them to test:
```csharp
var assetBundle = AssetBundle.LoadFromFile(Path.Combine(Application.streamingAssetsPath, "banks"));
if (assetBundle == null)
{
Debug.LogError("Failed to load AssetBundle!");
return;
}
foreach(var name in assetBundle.GetAllAssetNames())
{
FMODUnity.RuntimeManager.LoadBank(assetBundle.LoadAsset(name));
}
assetBundle.Unload(false);
```
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### Author:  [@vlad\_carx](https://qa.fmod.com/u/vlad_carx)
#### Post date: [June 5, 2026, 8:00am UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/9 "2026-06-05T08:00:56Z")
Thank you for your answers and thank you so much for your help!
We have resolved the issue. The problem was in the serialized fields. We had `TextAsset` serialized fields for the Master Bank to initialize the game. So, we serialized the banks and then loaded them via “RuntimeManager.LoadBank”. For some reason, it didn’t work with the `TextAsset` format, but it worked perfectly with “AssetReference”
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### Author:  [@Connor\_FMOD](https://qa.fmod.com/u/Connor_FMOD)
#### Post date: [June 7, 2026, 11:03pm UTC](https://qa.fmod.com/t/android-ios-error-could-not-load-bank-master-bank-err-format-unsupported-file-or-audio-format/24289/10 "2026-06-07T23:03:16Z")
Thank you for sharing the solution