A Granular (GRT) restore fails with -The media identifier does not represent a valid medium- because the IMG Media Type is missing in the Media Type list.
The Backup Exec Database is missing the IMG media type.
This can be confirmed by going to the Media Tab, Right click Properties on any media. In the top of the Properties dialog there is a Media Type listing and a button to the right. Click the button to open the Media Type dialog. In the top there is the Media Type List. Click the drop down and look for IMG in the list.
The issue is a corruption of the Database not having the media type.
A. Save the existing BE Database. Reload from a Base Database and recreate jobs.
B. Save the existing BE Database. Contact Symantec Support for a Script to add IMG back to the database. (Internal Note)
The IMG media is listed as Media Type ***
The Media Type list is missing IMG.