Component GUI Layer in Main Camera for Scene Assets/1_SelfDrivingCar/Scenes/ControlMenu.unity is no longer available.

[MrGT07]

Unity Version: 2019.4.27f1

After removing compilation errors I tried to build the sim
But it encountered several error listed below:

1. Component GUI Layer in Main Camera for Scene Assets/1_SelfDrivingCar/Scenes/ControlMenu.unity is no longer available.

2. UnityEditor.BuildPlayerWindow+BuildMethodException: 3 errors at UnityEditor.BuildPlayerWindow+DefaultBuildMethods.BuildPlayer (UnityEditor.BuildPlayerOptions options) [0x002bf] in <3d1d98bfb8b543c39074f81ee5a7c4a3>:0
   at UnityEditor.BuildPlayerWindow.CallBuildMethods (System.Boolean askForBuildLocation, UnityEditor.BuildOptions defaultBuildOptions) [0x00080] in <3d1d98bfb8b543c39074f81ee5a7c4a3>:0
   UnityEngine.GUIUtility:ProcessEvent (int,intptr)

3. TLS Allocator ALLOC_TEMP_THREAD, underlying allocator ALLOC_TEMP_THREAD has unfreed allocations, size 90 (This particular error has been encountered repeatedly)