Upgrading from Asset Store version of the FBX Exporter
If your previous version of the FBX Exporter package was version 1.3.0f1 or earlier, follow these steps:
Before you install the FBX Exporter Package, follow these steps (recommended):
Back up your Project.
Restart Unity.
Delete the FbxExporters folder.
Install the FBX Exporter from the Package Manager.
If you were using an older version of the FBX Exporter, some Assets in your Project may have missing scripts where the obsolete FbxPrefab component was used. To fix these issues, follow these steps:
If your Project Assets are serialized as Binary, select Edit > Project Settings > Editor to view the Editor Settings.
Change the Asset Serialization mode to Force Text. The Force Text option converts all Project Assets to text.
Before continuing, back up your Project.
Select Edit > Project Settings > FBX Export to view the FBX Export Settings.
Click the Run Component Updater button to repair all text serialized Prefab and Scene Assets in the Project containing the obsolete FbxPrefab component.