Unity2019 creating a new project reports an error

1错误出现过程

Unity2019安装后，重启电脑不幸蓝屏（同时还安装了其他多个软件），无奈只好还原到上一次的还原点。导致Unity2019重新安装后无法使用，创建新的项目即会报错。

估计别人很难会遇到这么奇葩的问题了，特此记录

Error: Could not load signature of Packages.Rider.Editor.UnitTesting.TestEvent:.ctor due to: Could not load file or assembly 'nunit.framework, Version=3.5.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb' or one of its dependencies. assembly:nunit.framework, Version=3.5.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb type:<unknown type> member:(null) signature:<none>

Library\PackageCache\com.unity.test-framework@1.1.11\UnityEngine.TestRunner\Assertions\AllocatingGCMemoryConstraint.cs(2,7): error CS0246: The type or namespace name 'NUnit' could not be found (are you missing a using directive or an assembly reference?)

2错误

原因

Unity创建Library首先会从缓存文件夹中复制，可能因为系统还原删除了某些缓存文件导致文件无法找到

解决方案

删除如下缓存即可