When working with Unity's new input system I found a bug and took a couple hours testing it out to find ways to workaround it and exactly how to reproduce it. This bug effects how action maps are saved in editor and I have a video showing how to reproduce it in a blank project. Tested in a new blank project Tested on Unity 2018.2.6f1 Unity 2018.3.b1 Input version 0.0.7 Do the following to reproduce Create a new input actions asset in the project folder Open it and add a new action map and name the map whatever Hit save After this create a new action map, binding or action. After you first create it click away. Double click on it and try to rename any of the actions, action maps, or bindings and hit enter to confirm. When you hit save it won't save and you get the error from the pictures. Notice it says NullReferenceException in console. Some notes if you right click on the action delete it than create a new one and change the initial name while creating the new one you can save now. Also if you hit F2 instead of double clicking to rename the action I found sometimes it doesn't give any error and most of the time seems to work with renaming whiles still allowing saving. It looks like it is trying to find the serialized asset in the project folder and since the name is being changed it can't properly reference the asset and causing a null reference making saving not possible. Not sure though. This is something for Unity devs to say. This is the only issue I have found with saving the asset. This is the biggest headache for me and probably others too so hopes this helps.