Having 452 errors when create a new empt project

Hello, i’m new on Unity, i have create my first 2D project with no problem.
But now, when I try to create a new one I’m having 452 errors like this one:

Library\PackageCache\com.unity.test-framework@1.1.27\UnityEngine.TestRunner\Assertions\InvalidSignatureException.cs(1,7): error CS0246: The type or namespace name ‘NUnit’ could not be found (are you missing a using directive or an assembly reference?)

I’m using the Unity Hub 2.4.5 and the Version 2020.3.15f2.

I have tried to remove the test-framework from the package manager, reinstall all the unity in another folder, another type like 3D or a Platform game, change the version to the 2021 and the 2019 and nothing change.
if anyone can help me i will be very grateful.

I did. I get the folder name packages.unity.com, and delete it
With all the folders inside
And reimported all from the assets
And the errors are gone