Your project is missing assets that other users have. This typically occurs when your project is not the same version as the Scene Fusion session host. Scene Fusion will create a temporary stand-in object of the same type as the missing asset. References to the missing asset will instead reference the stand-in object. The stand-in is named 'Missing [Asset Type] [Asset Path]', which will be shown in the inspector where the stand-in is referenced.
Scene Fusion displays a 'Missing Asset' notification in the notifications window. The game object(s) referencing the missing asset(s) have a yellow warning triangle instead of a green checkmark in the hierarchy. There is a warning in the console saying 'Unable to load [asset type] [asset path]'
Ensure everyone has the same version of the Unity project by performing the following steps.
If you are out of date with the project in source control:
If you have files not yet committed to source control:
Once you get the missing asset(s), Scene Fusion will automatically update references to the asset(s) and the notification will disappear.
Note: Ensure that the host of the session also has the most up to date version of the project by following the above steps.
Note: When you save the scene or disconnect from the session, stand-ins are converted to Unity missing asset references with the guid and local file id of the missing asset, so Unity will automatically replace the missing asset reference when the asset with that guid and local file id is added to the project.In order for Scene Fusion to set the local file id of the reference, you must set your project settings to use asset serialization mode 'ForceText'. This forces Unity to serialize assets as YAML text files. This is the default and recommended mode for projects that use source control. It does not affect who assets are serialized in game builds. You will be prompted to make this change if the serialization mode is not 'ForceText' when you join or start a session. If you do not use 'ForceText', missing asset replacement outside of a session may not work for subassets or prefabs, and you will either need to set the missing references manually or get the scene file from someone who has the correct asset references.
What if my team doesn't use source control?
We highly recommend using a source control solution. However, if you are not using source control, you can solve this issue by simply sharing the most up to date version of the Unity project with everyone who will be using Scene Fusion.