Invalid editor window UnityEditor.FallbackEditorWindow sinceupdated to 2019.4.12

Since updating to 2019.4.12, I keep getting this console error occasionally in play mode:

Invalid editor window UnityEditor.FallbackEditorWindow

I've already tried Layout -> Revert Factory Settings, and restarted Unity but I'm still seeing the error.

Anyone know if this is a regression in the latest 2019 LTS version? Or if that's just a coincidence? I'm not finding any other approaches to resolving this. Here's what my layout looks like: It's just standard Unity windows, plus ProBuilder:



I am having the same issue... constantly..
Reset... works fine for a time... same issue again..

1 Like

Same issue, and also the scene view is blank in the project for some scenes (though these scenes will still play, and the game view is populated). Unity editor gives the following error when I try to switch layouts (using: Window > Layouts > Default) or revert windows to factory settings:

ArgumentNullException: Value cannot be null.
Parameter name: dest

Same here, restarting the Layout only lasts for 1 session.

1 Like

Have this issue. Resetting layout helps only until next restart.

Same thing here :/

Same thing after upgrading from 2019.4.10f1 to 2019.4.13f1

I filled a bug report (Help > Report a bug...). I suggest that all of you also do this so they can see the issue and fix it.

After my bug report Unity sent me an email to track the issue, which is here:

Go there and vote so they can prioritize to fix it.


I have this same problem in 2022

Same issue here, popped up when I started using Gaia