New included music files are not displayed in Windows Media Player library
You include new music files in Library. However, they are not displayed in Windows Media Player library.
The Windows Media Player database is corrupted.
We need to delete the database and then re-add all of the media to the library. To archive this, please follow the steps below:
NOTE: These steps will delete system files. It is recommended to make a backup of any of these files before you do this, especially if you have purchased music via the online music shops. Your music will not be deleted, just the database.
1. Close Windows Media Player
To make sure Windows Media Player is closed, please open task manager by right clicking on the blank area and select “Start Task Manager”. If wmplayer.exe is still running under the Processes tab, highlight it and click “End Process”.
2. Clear Windows Media Player cache file
1) Open Windows Explorer and paste the following path into the address bar:
%USERPROFILE%\Local Settings\Application Data\Microsoft\Media Player\
The Window will open and you will see temp files inside.
2) Before deleting all the files, it is suggested to move all the content to another directory.
3) Select all the Items and Delete.
4) Restart Windows Media Player.
Then, you will notice all the music files you added appear in the library.