Configure Microsoft Volume Shadow copy Service (VSS)

Written By Tami Sutcliffe (Super Administrator)

Updated at October 6th, 2025

How to configure Microsoft Volume Shadow copy Service (VSS)

Microsoft Volume Shadow Copy Service (VSS) stores data on the drive in a hidden fashion, which leverages free space on the volume.  (You cannot see these shadow files but space consumed by shadow storage is reflected in the available free space on the volume.)  

We recommend setting a limit for the maximum size of shadow copy data, so that the volume will not be fully consumed with snapshot data.

Microsoft’s recommended default value for shadow storage is 10% of the volume size.

  • You can specify shadow storage limits in terms of either (a) a fixed amount of  space or (b) a percentage of the volume's total size. 
  • Shadow storage for one volume can be targeted to be stored on another volume, if there is not enough free space available locally.  

Examples of shadow copy commands

Open a cmd prompt with Run as Administrator to issue the following commands:


To resize shadow copy of volume C with a maximum size of 500GB:
vssadmin resize shadowstorage /For=C: /MaxSize=500GB

To resize shadow copy of volume C to 20% of its total capacity:
vssadmin resize shadowstorage /For=C: /On=C: /MaxSize=20%

To resize shadow copy of volume C on volume D, with a maximum size of 900MB:
vssadmin resize shadowstorage /For=C: /On=D: /MaxSize=900M




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