A similar trick to the Plex Dance:
Create a folder in that music directory and name it _temp, using an underscore makes it easier to find as it becomes the first folder on top.
Go to you library’s sub menu, shown below.
Select Scan Library Files first.
After that’s been completed, go back to the submenu and select Empty Trash. You can delete the underscored folder that you made once your changes have been reflected in the Library.
See if that helps.
