Thanks for testing and feedback! The blank window is actually the welcome window, it's fully loaded after all importing completes. The InitializeOnLoad attribute does not work to open this when an asset is imported, so I've setup a OnPostprocessAllAssets callback to make sure the window loads the first time a user imports the asset. I'll try to setup a solution for it to open after importing completes instead of when it starts. This is not currently a high priority for me, but it's on my list of stuff to improve. I'm using 2019.2.5 for my testing lately, the only error I get after import is about a missing tree from the terrains - I'll sort that out. I was able to reproduce the minimap error by quickly stopping the open world scene after pressing play, I've added null checks so it won't execute that line unless it exists - I believe this happened because the minimap canvas setup coroutine did not complete and was not fully loaded and assigned before the scene stopped. Most of the cleanup from the racing system is complete, I'll do a tutorial on it next. Then I'll begin work on the championship race mode.