error CS0006: Metadata file ‘Library/PackageCache/com.unity.collab-proxy@2.7.1/Lib/Editor/PlasticSCM_unity error cs0006

error CS0006: Metadata file \'Library/PackageCache/com.unity.collab-proxy@2.7.1/Lib/Editor/PlasticSCM/log4netPlastic.dll\' could not be found
error CS0006: Metadata file \'Library/PackageCache/com.unity.collab-proxy@2.7.1/Lib/Editor/PlasticSCM/Unity.Plastic.Antlr3.Runtime.dll\' could not be found
error CS0006: Metadata file \'Library/PackageCache/com.unity.collab-proxy@2.7.1/Lib/Editor/PlasticSCM/Unity.Plastic.Newtonsoft.Json.dll\' could not be found

问题原因：PlasticSCM Disk所使用的云服务已停止运营

解决方案：移除它就行了（com.unity.collab-proxy就是PlasticSCM

）

如果移除后还是不行，就去重新安装它，然后再移除就行了