How to resolve UnauthorizedAccessException

I'm trying to build and test my first game. I was successful in the past and had no UnauthorizedAccessException issues... I'm not exactly sure what I did to trigger this either. For the past several days I've done research and found my only solution was to delete the Library folder and reload Unity. Then the build(s) worked and I could download APKs to my mobile.

Now I'm trying to include ads and I've made some adjustments to my game.

Deleting the Library folder no longer resolves the issue. What do I have to do to fix this Extremely frustrating error? It is completely halting my development process.

Please. This is very frustrating for a rookie to deal with.

My Error : UnauthorizedAccessException: Access to the path "Library/BuildPlayerData\Editor" is denied. System.IO.Directory.Delete (System.String path) (at :0) System.IO.Directory.RecursiveDelete (System.String path) (at :0) System.IO.Directory.Delete (System.String path, System.Boolean recursive) (at :0) UnityEditor.VisualStudioIntegration.DirectoryIOProvider.Delete (System.String path, System.Boolean recursive) (at :0) UnityEditor.Build.Player.BuildPlayerDataGenerator.CreateCleanFolder (System.Boolean isEditor) (at :0) UnityEditor.Build.Player.BuildPlayerDataGenerator.GenerateForAssemblies (System.String[] assemblies, System.String[] searchPaths, UnityEditor.BuildTarget buildTarget, System.Boolean isEditor) (at :0) UnityEditor.Build.Player.BuildPlayerDataGeneratorNativeInterface.GenerateForAssemblies (System.String[] assemblies, System.String[] searchPaths, UnityEditor.BuildTarget buildTarget, System.Boolean isEditor) (at :0) UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)