Errors after updating Unity Version from 2018.2 to 2018.3

I had to upgrade my project from 2018.2.18 to 2018.3.2 because a feature I needed. After this all seemed normal, but when I modify a script with FMOD references, the inspector starts to show command errors.
I was told that could be because the FMOD manifest is refering to the old Unity version. How could I change it?
I tried as well to change FMOD version, to repair/Regenerate FMOD files so the manifest update, but I get an error as well.

The errors on Unity Editor are:

-GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced.

-NullReferenceException: Object reference not set to an instance of an object
UnityEditor.InspectorWindow.DisplayRemovedComponent (UnityEngine.GameObject go, UnityEngine.Component comp) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1353)

-NullReferenceException: Object reference not set to an instance of an object
UnityEditor.InspectorWindow.DisplayRemovedComponent (UnityEngine.GameObject go, UnityEngine.Component comp) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1353)

The error while upgrading FMOD is:
Copying Temp/Export Package/[…]/asset to Assets/Plugins/x86_64/fmodstudiol.dll: Access Denied

The integration should not be causing any issues like that, I would try closing Unity and deleting the Library folder (Unity will rebuild then when you open the Editor next).

Exactly what happened! Thanks! Seems like temporal files were messing with my project.