System Volume Information increase Daily Increase

Hello Brothers, 

System Volume Information increase Daily Increase and way to delete theses files

This windows 2012 server which is domain control and have Veritas Netbackup client installed. 

We try some command and 

PS C:\Windows\system32> vssadmin delete shadows /all

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001-2013 Microsoft Corp.

Error: Snapshots were found, but they were outside of your allowed context.  Try removing them with the

backup application which created them.

PS C:\Windows\system32> vssadmin delete shadows /for=D: /all

vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool

(C) Copyright 2001-2013 Microsoft Corp.

No items found that satisfy the query.

PS C:\Windows\system32>

Thanks,