How do I get rid of FMOD errors in the console: "An error occured that wasn't supposed to. Contact support."

I had the exact same issue (long repetition of exactly the same errors mentioned above). After much troubleshooting I discovered the solution for my situation:

I had a glitched prefab.

In my project, I have one root prefab that is duplicated over and over and the values are tweaked in the inspector. What I didn't notice is that the prefab had begun to take on children in the Project tab that should not have been there. Moreover, every time I duplicated the prefab, another one of these phantom children objects would be added.

So the problem compounded. By phantom, I mean that while I could select the child objects in the Project window, I could NOT DELETE THEM (tried right clicking, hitting delete, nothing worked). When I dragged one of these prefabs directly into the scene, Unity would stall for a long time as it tried to figure out whether there was a child there or not. Finally, after a long list of errors, the object would indeed appear with children in my scene. At that point I could delete the child objects from the prefab in the hierarchy, and then apply the changes to the original prefab.

One last thing I'll mention is that in my game I use a level editor to tweak the prefab public values. My level editor invokes 'SetDirty' to ensure changes to the prefab are saved. I imagine that somewhere during the SetDirty invocation the glitch happened.

I'll post a bug report/solution to Unity.

I'm intentionally abusing the editor to do some profiling out of curiosity. I get this error or a crash with the following code.

 void Start()
 {
     double iterations = 5000.0;
     Debug.Log("***** Start");
 
     GameObject root = new GameObject("root");
     root.AddComponent<SpriteRenderer>();
     root.AddComponent<AudioSource>();
     root.AddComponent<Light>();
     GameObject latest = root;
     using (new Timer("new GameObject()", iterations ))
     {
         for(int i = 0; i < (int)iterations ; ++i)
         {
             var go = new GameObject();
             go.AddComponent<SpriteRenderer>();
             go.AddComponent<AudioSource>();
             go.AddComponent<Light>();
             go.transform.parent = latest.transform;
             latest = go;
         }
     }
 
     Destroy(root);
 
     root = new GameObject("root");
     root.AddComponent<SpriteRenderer>();
     root.AddComponent<AudioSource>();
     root.AddComponent<Light>();
     latest = root;
 
     using (new Timer("GameObject.Instantiate", iterations ))
     {
         for (int i = 0; i < (int)iterations ; ++i)
         {
             var go = Instantiate(latest) as GameObject;
             go.transform.parent = latest.transform;
             latest = go;
         }
     }
 
     Destroy(root);
 
     Timer.PrintAll();
 }

For the curious, the timer used in this code is this:

 class Timer : IDisposable
 {
     private readonly string m_Text;
     private Stopwatch m_Stopwatch;
     private double m_DivBy;
 
     private static List<string> m_Backlog = new List<string>();
 
     public Timer(string text, double divBy = 0.0)
     {
         m_Text = text;
         m_DivBy = divBy;
         m_Stopwatch = Stopwatch.StartNew();
     }
 
     public void Dispose()
     {
         m_Stopwatch.Stop();
         if (m_DivBy != 0.0)
         {
             m_Backlog.Add(string.Format("Profiled {0}: {1} seconds. {2} milliseconds.", m_Text, m_Stopwatch.Elapsed.TotalSeconds / m_DivBy, m_Stopwatch.Elapsed.TotalMilliseconds / m_DivBy));
         }
         else
         {
             m_Backlog.Add(string.Format("Profiled {0}: {1} seconds. {2} milliseconds.", m_Text, m_Stopwatch.Elapsed.TotalSeconds, m_Stopwatch.Elapsed.TotalMilliseconds));
         }
 
     }
 
     public static void PrintAll()
     {
         foreach(var result in m_Backlog)
         {
             Debug.Log(result);
         }
     }
 }

Running 5000 iterations causes this error to occur.

Running 10000 iterations is a 100% crash of the editor with no crash reporter.