"WebGL error: ""Could not produce class with ID 0""" (181479)

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Hi, I am working on a WebGL project with asset bundles. Everything seems to work but I am getting the following error even when I disable ‘Strip Engine Code’. Any thoughts? I don’t find any reference to a class with ID 0.

blob:http://localhost:8000/d89a9c3f-9b5c-49a3-8e70-0ca3b59f0227:8336 Could not produce class with ID 0.
This could be caused by a class being stripped from the build even though it is needed. Try disabling ‘Strip Engine Code’ in Player Settings.

(Filename: /Users/builduser/buildslave/unity/build/Runtime/Serialize/PersistentManager.cpp Line: 1323)

When I recently added an animated character to my project, this error showed up again. This time the missing class was UnityEngine.Avatar (after a lot of trial/error). Upon closer inspection, it should be noted that the Animator component does have a reference to Avatar, so I guess that makes sense. Still, this might help someone who has the same problem.

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Have the same error and can't find what class 0 should be. Have you found out? All other classes are listed here: https://docs.unity3d.com/Manual/ClassIDReference.html

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3 Answers

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Hi, just to share what I ended up doing, maybe it can help you @Milchbar.

What I noticed was that I was missing some particles, so what I did was start adding as much namespaces related to particles I could think of. That solved the issue but then I started commenting out to see which were really necessary.

<linker>
    <assembly fullname="UnityEngine">
	    <type fullname="UnityEngine.MeshRenderer" preserve="all"/>
	    <type fullname="UnityEngine.SkinnedMeshRenderer" preserve="all"/>
	    <type fullname="UnityEngine.MeshFilter" preserve="all"/>
	    <!--<type fullname="UnityEngine.MeshCollider" preserve="all"/>-->
	    <!--<type fullname="UnityEngine.BoxCollider" preserve="all"/>-->
	    <!--<type fullname="UnityEngine.Sprite" preserve="all"/>-->
	    <!--<type fullname="UnityEngine.SpriteRenderer" preserve="all"/>-->
	    <!--<type fullname="UnityEngine.ParticleAnimator" preserve="all"/>
	    <type fullname="UnityEngine.ParticleEmitter" preserve="all"/>-->
	    <type fullname="UnityEngine.PhysicMaterial" preserve="all"/>
	    <type fullname="UnityEngine.ParticleSystemRenderer" preserve="all"/>
    </assembly>
</linker>

I figured that the particles were the issue because I had two particle emitters and got two “Could not produce class with ID 0” errors on the log.

Hope it helps.

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I have the same issue with class 1049652922 - how did you go about including the UnityEngine.Avatar class?

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Have the same error and can’t find what class 0 should be. Have you found out? All other classes are listed here: Unity - Manual: Classes ordered by ID number

I create a new empty project, I still can't open unity, so this is not my project problem. Now I reinstall my macOS system, when I reinstall unity I can open unity. I think maybe I can't install Unity5.x with Unity 2017, and when Unity uninstall it leave something in macOS.

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