PathToGUID doesn't work on iOS64.

[mutoo]

I would try testing your code with the Mono backend if possible (I know that it’s impossible to submit to the store). 5.1.4 is old and there have been IL2CPP bugs affecting ‘script’ to native library function calls.

You can test if the strings bank is loaded.

    // Right click an event in the tool and select copy GUID
    // {e9b7aafa-2df0-4193-b32e-a74e5753cfa0}
    System.Guid guid = new System.Guid(0xe9b7aafa, 0x2df0, 0x4193, 0Xb3, 0x2e, 0xa7, 0x4e, 0x57, 0x53, 0xcf, 0xa0);
    FMOD.Studio.EventDescription desc;
    FMODUnity.RuntimeManager.StudioSystem.getEventByID(guid, out desc);
    string path;
    desc.getPath(out path);
    Debug.LogFormat("Path = {0}", path);

Path will be empty if the string bank failed to load.

Thanks for your answer. I just tested this code, and I did get empty path. Maybe I should try upgrading unity3d to a newer version.