Bug Errors when opening player settings

Hi, I have a problem with the editor. whenever I try to open player settings I receive errors and the screen is blank (2020.2.3f1 URP)

Info:
This is a Collaborate project and I'm the owner (I am the only one currently working on it)



Error 1:

Code (CSharp):

1. TypeLoadException: Type UnityEditor.WebGL.WebGLTemplateManager has invalid vtable method slot 4 with method none
2. UnityEditor.WebGL.TargetExtension.CreateSettingsEditorExtension () (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/ExtensionModule.cs:20)
3. UnityEditor.Modules.ModuleManager.GetEditorSettingsExtension (System.String target) (at <a936841cea2147a2a55ea27843fa46ae>:0)
4. UnityEditor.PlayerSettingsEditor.OnEnable () (at <a936841cea2147a2a55ea27843fa46ae>:0)
5. UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)
6.  

Error 2:

Code (CSharp):

1. NullReferenceException: Object reference not set to an instance of an object
2. UnityEditor.PlayerSettingsEditor.SetValueChangeListeners (UnityEngine.Events.UnityAction action) (at <a936841cea2147a2a55ea27843fa46ae>:0)
3. UnityEditor.PlayerSettingsEditor+<>c__DisplayClass245_0.<CreateProjectSettingsProvider>b__0 (System.String searchContext, UnityEngine.UIElements.VisualElement rootElement) (at <a936841cea2147a2a55ea27843fa46ae>:0)
4. UnityEditor.SettingsProvider.OnActivate (System.String searchContext, UnityEngine.UIElements.VisualElement rootElement) (at <a936841cea2147a2a55ea27843fa46ae>:0)
5. UnityEditor.AssetSettingsProvider.OnActivate (System.String searchContext, UnityEngine.UIElements.VisualElement rootElement) (at <a936841cea2147a2a55ea27843fa46ae>:0)
6. UnityEditor.SettingsWindow.ProviderChanged (UnityEditor.SettingsProvider lastSelectedProvider, UnityEditor.SettingsProvider newlySelectedProvider) (at <a936841cea2147a2a55ea27843fa46ae>:0)
7. UnityEditor.SettingsTreeView.SelectionChanged (System.Collections.Generic.IList`1[T] selectedIds) (at <a936841cea2147a2a55ea27843fa46ae>:0)
8. UnityEditor.IMGUI.Controls.TreeViewController.NotifyListenersThatSelectionChanged () (at <a936841cea2147a2a55ea27843fa46ae>:0)
9. UnityEditor.IMGUI.Controls.TreeViewController.NewSelectionFromUserInteraction (System.Collections.Generic.List`1[T] newSelection, System.Int32 itemID) (at <a936841cea2147a2a55ea27843fa46ae>:0)
10. UnityEditor.IMGUI.Controls.TreeViewController.SelectionClick (UnityEditor.IMGUI.Controls.TreeViewItem itemClicked, System.Boolean keepMultiSelection) (at <a936841cea2147a2a55ea27843fa46ae>:0)
11. UnityEditor.IMGUI.Controls.TreeViewController.HandleUnusedMouseEventsForItem (UnityEngine.Rect rect, UnityEditor.IMGUI.Controls.TreeViewItem item, System.Int32 row) (at <a936841cea2147a2a55ea27843fa46ae>:0)
12. UnityEditor.IMGUI.Controls.TreeViewController.DoItemGUI (UnityEditor.IMGUI.Controls.TreeViewItem item, System.Int32 row, System.Single rowWidth, System.Boolean hasFocus) (at <a936841cea2147a2a55ea27843fa46ae>:0)
13. UnityEditor.IMGUI.Controls.TreeViewController.IterateVisibleItems (System.Int32 firstRow, System.Int32 numVisibleRows, System.Single rowWidth, System.Boolean hasFocus) (at <a936841cea2147a2a55ea27843fa46ae>:0)
14. UnityEditor.IMGUI.Controls.TreeViewController.OnGUI (UnityEngine.Rect rect, System.Int32 keyboardControlID) (at <a936841cea2147a2a55ea27843fa46ae>:0)
15. UnityEditor.IMGUI.Controls.TreeView.OnGUI (UnityEngine.Rect rect) (at <a936841cea2147a2a55ea27843fa46ae>:0)
16. UnityEditor.SettingsWindow.DrawTreeView () (at <a936841cea2147a2a55ea27843fa46ae>:0)
17. UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <52128b1d503447a983e9b80962adef7d>:0)
18. UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, UnityEngine.Matrix4x4 worldTransform, UnityEngine.Rect clippingRect, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <52128b1d503447a983e9b80962adef7d>:0)
19. UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <52128b1d503447a983e9b80962adef7d>:0)
20. UnityEngine.UIElements.IMGUIContainer.HandleIMGUIEvent (UnityEngine.Event e, System.Boolean canAffectFocus) (at <52128b1d503447a983e9b80962adef7d>:0)
21. UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUIRaw (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <52128b1d503447a983e9b80962adef7d>:0)
22. UnityEngine.UIElements.IMGUIContainer.SendEventToIMGUI (UnityEngine.UIElements.EventBase evt, System.Boolean canAffectFocus, System.Boolean verifyBounds) (at <52128b1d503447a983e9b80962adef7d>:0)
23. UnityEngine.UIElements.IMGUIContainer.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <52128b1d503447a983e9b80962adef7d>:0)
24. UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at <52128b1d503447a983e9b80962adef7d>:0)
25. UnityEngine.UIElements.MouseEventDispatchingStrategy.SendEventToRegularTarget (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <52128b1d503447a983e9b80962adef7d>:0)
26. UnityEngine.UIElements.MouseEventDispatchingStrategy.SendEventToTarget (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.BaseVisualElementPanel panel) (at <52128b1d503447a983e9b80962adef7d>:0)
27. UnityEngine.UIElements.MouseEventDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel iPanel) (at <52128b1d503447a983e9b80962adef7d>:0)
28. UnityEngine.UIElements.EventDispatcher.ApplyDispatchingStrategies (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, System.Boolean imguiEventIsInitiallyUsed) (at <52128b1d503447a983e9b80962adef7d>:0)
29. UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <52128b1d503447a983e9b80962adef7d>:0)
30. UnityEngine.UIElements.EventDispatcher.ProcessEventQueue () (at <52128b1d503447a983e9b80962adef7d>:0)
31. UnityEngine.UIElements.EventDispatcher.OpenGate () (at <52128b1d503447a983e9b80962adef7d>:0)
32. UnityEngine.UIElements.EventDispatcherGate.Dispose () (at <52128b1d503447a983e9b80962adef7d>:0)
33. UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <52128b1d503447a983e9b80962adef7d>:0)
34. UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <52128b1d503447a983e9b80962adef7d>:0)
35. UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <52128b1d503447a983e9b80962adef7d>:0)
36. UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <52128b1d503447a983e9b80962adef7d>:0)
37. UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& eventHandled) (at <52128b1d503447a983e9b80962adef7d>:0)
38. UnityEngine.UIElements.UIEventRegistration.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at <52128b1d503447a983e9b80962adef7d>:0)
39. UnityEngine.UIElements.UIEventRegistration+<>c.<.cctor>b__1_2 (System.Int32 i, System.IntPtr ptr) (at <52128b1d503447a983e9b80962adef7d>:0)
40. UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& result) (at <f8197c5efb504ab8a77daf7d0e9abc5e>:0)
41.  

 

I was having the same issue.

Turns out I had accidentally installed a mismatched version of the WebGL build support module.

Uninstalling/reinstalling the module worked for me.

Hope that helps.