Available_media.cmd command is helpful to find out the media status in Veritas Netbackup. If you run the below command to see the status of media you may encountered below error
You are already running Available_Media.
Try again later.
How to resolve this
There is a tech note available in symantec that how we can resolve this error.
you have to delete the AM.<USERNAME>.lok file, from %temp% folder then run the Available_Media.cmd script again
Thought to share this error with all of you and hope it helps some one who is working with Symantec Veritas Netbackup