Some FMOD Event assets changed on every Editor launch

Unreal Engine
1

My team recently updated to UE 5.5.3 and FMOD 2.03.05. We are now encountering an issue where some FMOD Event assets need to be resaved every time the editor is opened and ReloadBanks runs for the first time. In attempting to narrow down why this is happening, it appears to be the case that any FMOD Event asset that is referenced by a GameplayCueNotify_Actor asset could wind up needing to be resaved. In stepping through FFMODAssetBuilder code what I am seeing is that in CreateAsset a UPackage is successfully created by CreatePackage, but then FindObject returns null because the package doesn’t contain anything. It then tries to create a NewObject, which winds up with the same GUID but other values changed, one of which also looks like a GUID but perhaps pointing out to a parent or something. That number changes every time banks are reloaded when the Editor opens.

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It fails to save the new asset because “AsyncRoot still associated with Linker” (see LinkerLoad.cpp). By best guess is that this means that the FMOD Event asset is in the process of being asynchronously loaded by the GamplayCueNotify_Actor asset that is referencing it when ProcessBanks is called after the FMOD Studio Editor Module startup. I can see that this is supposed to trigger after the asset register has finished loading, but wonder if that event doesn’t include async loading or something like that.

I’ve attempted to create a simple repro case in a separate UE project, but have not been able to reproduce it so far.

2

It sounds similar to a long standing issue with blueprints being loaded before FMOD, which I believe was more about in PIE/game but sounds like it may be relevant.

I have not been able to repro it myself but do send through a project if you can.

3

Thanks @cameron-fmod, reading that documentation gave me the idea to check the initialization order of the FMOD Studio plugin and the first time GameplayCueNotify assets are loaded from disk at startup. I found that the default loading behavior for GameplayCueNotify assets is async, which explains what I was seeing in my debugging. I was able to fix the issue by overriding ShouldSyncLoadRuntimeObjectLibraries and ShouldAsyncLoadRuntimeObjectLibraries in our project’s GameplayCueManager subclass so that when in the Editor, Gameplay Cues are loaded synchronously.

I’m not really sure how the FMOD Studio plugin could account for this, but it seems to be the case that as of UE 5.5.3 the AssetRegistry hook being used to reload banks at startup is not accounting for async loads still in progress.