SceneManager.LoadScene(string) doesn't work

Unity Engine
2

Anytime you find yourself saying “This API doesn’t work!” when in fact that API is in use by MILLIONS of people around the world, it’s almost certain that you’re using it incorrectly.

First stop should be back at the documentation to make sure you’re meeting 100% of the specified requirements. Did you spell it correctly? Add it to the scene list? NOT append .unity to it? etc.

Rather than layering system on top of system on top of system (there are THREE different things in play above!), strip it down to ONE LINE OF CODE and make it work with a hard-coded scene name.

While you’re at it, be extremely explicit:

UnityEngine.SceneManagement.SceneManager.LoadScene( "MySceneName");

And you’ll find that either it works, or it gives you an error if you failed to add the MySceneName to your build settings. Make sure you’re seeing errors in the log.

Make sure your log console selector buttons are enabled. See this graphic:

Once you have contented yourself that the API does in fact work, turn your attention to your various blobs of code and start to figure out why they are NOT giving you the correct scene name, or even perhaps calling the right line of code.

What is often happening in these cases is one of the following:

  • the code you think is executing is not actually executing at all
  • the code is executing far EARLIER or LATER than you think
  • the code is executing far LESS OFTEN than you think
  • the code is executing far MORE OFTEN than you think
  • the code is executing on another GameObject than you think it is
  • you’re getting an error or warning and you haven’t noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

  • is this code even running? which parts are running? how often does it run? what order does it run in?
  • what are the values of the variables involved? Are they initialized? Are the values reasonable?
  • are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target.

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

You must find a way to get the information you need in order to reason about what the problem is.

If you just need a scene utility, here’s an easy-cheesy one I use in all my games:

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