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Fixed in 2019.1.X

Fixed in 2019.2.X



Found in



Issue ID




"ArgumentException: Object at index 0 is null" thrown when entering play mode with two Inspector windows and an attached script

Inspector Framework


How to reproduce:
1. Create a new project
2. Create a c# script and attach it to any object in the Hierarchy window
3. Add second Inspector window
4. Enter Play mode
5. Observe Console window

Expected result: no errors are thrown
Actual result: "ArgumentException: Object at index 0 is null" is thrown

Reproducible with: 2019.1.0b2, 2019.1.0f2, 2019.2.0a13, 2019.3.0a1
Not reproducible with: 2017.4.26f1, 2018.3.14f1, 2019.1.0b1

Comments (15)

  1. kousarseo

    Sep 30, 2020 11:49

    Only strive to mention one's content can be as incredible. This clarity with your post is superb! Thanks a lot, hundreds of along with you should go on the pleasurable get the job done.

  2. tconkling

    Oct 14, 2019 17:56

    This continues to happen for me in 2019.1.14f1 on Mac.

    Is there any chance of getting the fix backported to 2019.1?

  3. crafTDev

    Aug 30, 2019 16:37


    This still happens in MacOS Unity 2019.2.0f1

    I had 2 Inspectors open. To fix I had to close both inspectors.


  4. LorenzoNuvoletta

    Aug 26, 2019 04:00

    In 2019.2.0 it happens when you have 2 inspectors open.

  5. pryankster

    Jul 21, 2019 02:47

    Though I hate to add a "me, too" to this bug: I have noticed that I get the error when I have two inspectors open, and the FIRST inspector is showing (locked or unlocked) a GameObject with a script attached. No script? no error.

  6. MrLucid72

    Jul 15, 2019 14:57

    Still happens in Unity 2019.1.8f1, easily repro'd by the multiple mentions above ^

  7. Adrian-Miasik

    Jul 15, 2019 00:31

    I've also managed to get this error on 2019.3.0a3 - Removing my second inspector window has prevented the error from showing up in the console and allows my editor scripts to execute properly.

  8. Zahidylin_Marat

    Jul 09, 2019 05:58

    The same issue after upgrading project from Unity 2018 to 2019.1.9f1.

    I had 2 Inspector tabs open. If you close one the error should go away.

  9. joonturbo

    Jul 05, 2019 17:05

    happens every time I hit play on 2019.1.8f1 on macOS

  10. Blenderik

    Jun 17, 2019 12:51

    I only use one Editor and this exact error happens everytime I press play in all my projects since upgrade to 2019.

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