# "Unsupported type EventReference" error when saving prefabs with Timeline in Unity Editor

**URL:** <https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041>\
**Category:** Unity\
**Tags:** unity\
**Created:** [February 17, 2026, 6:59pm UTC](https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041 "2026-02-17T18:59:32Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![VoodooDetective](https://avatars.discourse-cdn.com/v4/letter/v/ecc23a/32.png) [@VoodooDetective](https://qa.fmod.com/u/VoodooDetective)\
**Post date:** [February 17, 2026, 6:59pm UTC](https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041/1 "2026-02-17T18:59:32Z")

</div>

I’m encountering an editor-only console error when viewing and saving prefabs that contain Unity Timeline tracks with FMOD event playables:

```csharp
Unsupported type EventReference
UnityEditor.EditorApplication:Internal_CallGlobalEventHandler ()

```

**Environment:**

- Unity Version: 6000.2.10f1

- FMOD Unity Integration Version: 2.03.09

- Platform: macOS

**When it occurs:**  
The error appears specifically when:

1. Opening a prefab in the Unity Editor that contains Timeline tracks

2. Saving changes to these prefabs

3. The Timeline contains `FMODEventPlayable` assets

**Technical details:**  
The error seems to occur when Unity’s serialization system encounters the `EventReference` struct. The struct is properly marked with `[Serializable]` and works correctly at runtime, but Unity’s Timeline serialization path appears to have issues with the custom type.

Looking at the code, `EventReference` is used in:

- `FMODEventPlayable.EventReference` (line 27 of FMODEventPlayable.cs)

- `FMODEventPlayableBehavior.EventReference` (line 189 of FMODEventPlayable.cs)

**Impact:**

- This appears to be an editor-only warning

- Audio events seem to function correctly at runtime

- Prefab changes are saved successfully

- No actual functionality appears to be broken

**Question:**  
Is this a known issue with Unity’s Timeline system and the `EventReference` type? Is there a recommended workaround or will this be addressed in a future FMOD integration update?

---

<div class="post-metadata">

**Author:** ![VoodooDetective](https://avatars.discourse-cdn.com/v4/letter/v/ecc23a/32.png) [@VoodooDetective](https://qa.fmod.com/u/VoodooDetective)\
**Post date:** [February 18, 2026, 12:03am UTC](https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041/2 "2026-02-18T00:03:43Z")

</div>

This is a Unity serialization bug.

---

<div class="post-metadata">

**Author:** ![cameron-fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/cameron-fmod/32/261_2.png) [@cameron-fmod](https://qa.fmod.com/u/cameron-fmod)\
**Post date:** [February 27, 2026, 3:23am UTC](https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041/3 "2026-02-27T03:23:48Z")

</div>

I’d just like to confirm that this is no longer an issue for you, as it appears to be an issue with Unity’s serialization?

---

<div class="post-metadata">

**Author:** ![VoodooDetective](https://avatars.discourse-cdn.com/v4/letter/v/ecc23a/32.png) [@VoodooDetective](https://qa.fmod.com/u/VoodooDetective)\
**Post date:** [February 27, 2026, 7:05am UTC](https://qa.fmod.com/t/unsupported-type-eventreference-error-when-saving-prefabs-with-timeline-in-unity-editor/24041/4 "2026-02-27T07:05:53Z")

</div>

Yep, it’s Unity’s bug. Thanks for checking in.