Syntax: WBADMIN DISABLE BACKUP -quiet Description: Stops running the existing scheduled daily backups. To use this command, ...

Syntax: WBADMIN DISABLE BACKUP [-quiet]

Description: Stops running the existing scheduled daily backups.
To use this command, you must be a member of the Backup Operators group 
or Administrators group. 

Parameters:
-quiet          Runs the command with no prompts to the user.

Remarks:  If you stop the scheduled backups, the disks where you stored the 
backups cannot be used again to store backups until they are reformatted (so 
that all existing backups are deleted).