MissingReferenceException is thrown in the Hierarchy window when entering Play mode with a scene that contains an ECS SubScene

Unity: Core Runtime

Entities

In Progress

6.5.X

6000.5.3f1 onwards

Steps to reproduce:
1. Open the attached “IN-147877” Project
2. Open the SampleScene
3. Enter Play mode
4. Observe the console

Actual result: “MissingReferenceException” is thrown repeatedly. The Hierarchy window becomes unusable, as clicking any item throws the exception
Expected result: The Hierarchy window works with no errors

Reproducible with: 6000.5.3f1, 6000.5.4f1
Not reproducible with: 1.4.7 (6000.3.20f1), 6000.5.2f1, 6000.6.0b4, 6000.7.0a2

Reproducible on: macOS 26.5 (M1), Windows 11 (By reporter)
Not reproducible on: No other environments tested

Notes:

On stream 6000.6.X and 6000.7.X the bug is replaced with a memory leak warning
On stream 6000.5.X if Hierarchy V2 is enabled the bug disappears

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MissingReferenceException is thrown in the Hierarchy window when entering Play mode with a scene that contains an ECS SubScene

Unity: Core Runtime

Statuses

In Progress

Resolution Notes

Description

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Have a workaround or additional info about this issue?

MissingReferenceException is thrown in the Hierarchy window when entering Play mode with a scene that contains an ECS SubScene

Unity: Core Runtime

Statuses

In Progress

Resolution Notes

Description

Prioritise and Follow this issue

Have a workaround or additional info about this issue?