In my Unity project I am facing an unknown error and error of loading library files

Question

when I load my unity project it is showing me the 2 errors because of which I can't run my project. The errors are:

Unknown error occurred while loading 'Library/Artifacts/22/22ec59139bb4d4489ae56859248015ff'.

...and:

Library\PackageCache\com.unity.test-framework@1.1.29\UnityEngine.TestRunner\NUnitExtensions\Runner\TestCommandBuilder.cs(65,31): error CS0246: The type or namespace name 'ImmediateEnumerableCommand' could not be found (are you missing a using directive or an assembly reference?). If anybody will help me to understand these issues. I am using unity version 2021.1.25f1 and editor for C# script is visual studio 2022

Answer 1

This would occur when the version of your com.unity.test-framework package does not match the version of Unity editor you are using. Basically, there is a mismatch somewhere. I recommend going to your Windows > Asset Manager editor window, find all test related packages, and try to update them or uninstall/reinstall.

The most common cause for this issue is when someone upgrades the version of Unity that they are using (or downgrades), but doesn't go to check the compatibility of existing packages with the new Unity version. It can happen for other reasons, so I am not saying for sure that you changed Unity versions. But more often than not, this will fix your issue.