Unity Editor Freeze On Application.UpdateScene

Hey, i am facing a problem causing the editor to freeze on Application.UpdateScene after opening the project and move on it windows for sometime. i have to end task the editor and open it again. this start to happen without any reasonable reason as the project was working fine. i waked up next day open it then boom this problem start. i have tried many editor LTS versions still same issue. also tried to delete and re-import all project files still same. (note it happen without even clicking on play). i had the same problem with different project but i manage to fix it by reverting the scene file throw source control but i can’t fix it on this project.

i will go crazy cause of it and i am trying to fix this for 2 weeks now. kindly help me !!!

Editor Version : 2020.3…20 (LTS)

Version Control : Plastic SCM

Editor Logs: Attached
[187812-editor.txt|187812]
Screenshot:

Package Manager Logs :

[2021-10-21T16:00:11.124Z][INFO]
Command-line:
E:\Unity\UnityEditor\2020.3.20f1\Editor\Data\Resources\PackageManager\Server\UnityPackageManager.exe
-s 7356 -p 53013 -l 2 [2021-10-21T16:00:11.132Z][INFO]
Creating server instance
[2021-10-21T16:00:11.177Z][INFO]
Starting Server
[2021-10-21T16:00:11.183Z][INFO]
Server started on port [53013]
[2021-10-21T16:00:11.534Z][INFO] GET
‘/health’ ← Request received
[2021-10-21T16:00:11.536Z][INFO] GET
‘/health’ → 200 (2 ms)
[2021-10-21T16:00:14.500Z][INFO] GET
‘/project/registries’ ← Request
received
[2021-10-21T16:00:14.515Z][INFO] GET
‘/project/registries’ → 200 (14 ms)
[2021-10-21T16:00:16.936Z][INFO] GET
‘/project/registries’ ← Request
received
[2021-10-21T16:00:16.941Z][INFO] GET
‘/project/registries’ → 200 (4 ms)

if anyone face this on the future, i manage to fix the problem by debugging for some hours following this great guys steps :

anyway the cause was cinemachine dolly track specially CinemaMachineSmoothPath Script, i was using one waypoint as default value for waypoints, because i didn't need to specify more i have a script was assigning them on the runtime. So the editor was looping for no reason before clicking on the play button causing it to freeze like above.

how did u figure out which thread was actually the problem?