Fix Invalid security token error

The Library folder is a system-protected file. So first we need to enable Show Hide Files & Folder and Show Hide system protected file as well.

Rebuild Windows Media Center Library

Now that you have enabled these options to follow the below steps:

Press Win + R and type in %Programdata% and press EnterThen type Open Microsoft folder, then eHomeNow you’ll see a file called mediacenterdatastore.DB.Delete that file and reboot the system

After the reboot, the Windows Media Center seemed to work fine. I am sure that this way will help you too, should you face a similar problem.