The error "Unity not loading scene" can arise due to various reasons:
Incorrect scene name or path: The most common reason is a typo or incorrect case in the scene name or file path. Unity is case-sensitive, so ensure that the name of your scene matches exactly with the string you're using in your code.
Scene is not in the Build Settings: Another frequent cause is not having the scene added inside 'Scenes in Build' in the Build Settings window. If the scene isn't there, Unity won't be able to load it.
Issue with async loading: If you're using
SceneManager.LoadSceneAsync to load the scene, and it's not loading, it might be because the scene is being unloaded before it has finished loading. This can happen if an error occurs during the loading process.
Corrupted or missing files: Occasionally, a project or scene file may become corrupted or missing due to version control mishaps or disk errors.
Check scene name/path: Verify that the name of your scene and its path matches precisely with what you've written in your code.
Add scene to Build Settings: Open the Build Settings window (File > Build Settings), and make sure your scene is listed under 'Scenes in Build.' If it's not, you can add it by clicking on the 'Add Open Scenes' button.
Error handling with async loading: When using
SceneManager.LoadSceneAsync, make sure to have error handling in place to catch potential issues during the loading process. Also, ensure that you're allowing enough time for the scene to fully load before attempting to unload it.
Check for corrupted or missing files: If Unity reports a problem with the scene file itself (like "file not found" or "file is corrupted"), you might need to restore the file from backup, or re-import it, if possible. If version control was used, consider checking for any ignored files that may be essential to load the scene.