UI Toolkit "Unknown property id" errors are thrown in the Console when opening the project

Unity: UI Toolkit Framework

Won't Fix

6.7.X

6.6.X

6.5.X

6000.5.0a1 onwards

Thank you for reporting a bug to Unity. We have reviewed the issue carefully, and in this case, the bug is not possible to fix. A better error message have been introduced in 6000.7.0a3 but we can't support using pre-imported stylesheet/theme assets from one version to another because they are binary-incompatible. The current flow expect the asset to be imported from source in the current version of the editor.

How to reproduce:
1. Open the attached "IN-145911_LunyScript_Demo_Unity_6.5.zip" project
2. Open the "Simulator Survivors Demo" scene
3. Observe the Console

Actual result: Around 30 "Unknown property id" errors are thrown in the Console and the UI elements in Game view are all at the top of the screen
Expected result: No errors are thrown in the Console and the UI elements are in the positions that they are arranged in the UI Builder

Reproducible with: 6000.5.0a1, 6000.5.2f1, 6000.6.0b2, 6000.7.0a1
Not reproducible with: 6000.0.78f1, 6000.3.19f1, 6000.4.0a3

Reproducible on: Windows 11, macOS 26.5
Not reproducible on: No other environments tested

Note: One of the error messages (full):
”Unknown property id 458753
UnityEngine.UIElements.UIElementsRuntimeUtilityNative:UpdatePanels ()”

UI Toolkit "Unknown property id" errors are thrown in the Console when opening the project

Unity: UI Toolkit Framework

Won't Fix

Prioritise and Follow this issue

Have a workaround or additional info about this issue?

UI Toolkit "Unknown property id" errors are thrown in the Console when opening the project

Unity: UI Toolkit Framework

Statuses

Won't Fix

Resolution Notes

Description

Prioritise and Follow this issue

Have a workaround or additional info about this issue?