About Windows VSS | All You Should Know

Rel updated on Mar 22, 2023 | Home > Knowledge Center

What Is Windows VSS

Volume Shadow Copy Service (Windows VSS) is a technology included in Microsoft Windows, which provides a framework for Windows to perform volume backups and create consistent point-in-time data copies which are called shadow copies. 

windows vss

It allows you to back up or snapshot the computer files or volumes that are in use or not. The VSS runs by taking so-called a copy on write snapshot of your system. This technology relies on the NTFS file system to create and save shadow copies. The process requires VSS Service, VSS Provider, VSS Requester, and VSS Writer. The process can be automatic or manual. 

If you want to know more about the file system, read this post: ReFS vs NTFS: Which Is Better

VSS Architecture                                     

In the architecture of VSS, 3 terms are very important.

  • VSS Requestor: Requestor refers to an application that can request snapshots. The request will then be sent to the Provider
  • VSS Provider: In the field of VSS, the Provider will provide VSS services and coordinate all elements. In essence, VSS Provider is the core of VSS.
  • VSS Writers: After the VSS Provider notifies that the snapshot has been created, VSS Writers need to perform corresponding operations. After taking the snapshot, the provider will notify the writers. Then they will let the apps resume.

VSS History

VSS was originally introduced in Windows XP and can create shadow copies on local or external volumes. 

In Windows 7, people can create a shadow copy through backup and restore or the System Restore Point and use the previous version tab.

In Windows 8/10, you can use the file history function. But after Windows 8, Microsoft deleted the local volumes. Therefore, in Windows 8/10, you need to use ShadowExplorer to view or restore shadow copies.

The Main Benefits of VSS

The running process of VSS will allocate temporary storage space. Each time a part of the disk is written, the information on the disk will be copied to the snapshot first and then can be written.

The operating technology of VSS makes it very effective. The snapshot only contains changed data, and information writing only affects the used space, not the available space.

At the same time, VSS has another advantage. When more content is written, the more content VSS needs to store. If you perform multiple disk activities during the image period, the storage space of the snapshot may become larger. The existence of VSS can set an upper limit for the space size. If the snapshot size exceeds the upper limit, VSS will stop writing and delete the temporary storage.


Volume Shadow Copy Service is a feature of Microsoft Windows that represents volume shadow storage. Through this article, we introduce Windows VSS to you from three aspects: its definition, structure and history. At the same time, we also explained the main advantages of VSS in detail for you. After reading all contents, we hope you can get the information you want about VSS.

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Updated by Daisy

Daisy is the Senior editor of the writing team for EaseUS. She has been working in EaseUS for over ten years, starting from a technical writer to a team leader of the content group. As a professional author for over 10 years, she writes a lot to help people overcome their tech troubles.

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Written by Rel

Rel has always maintained a strong curiosity about the computer field and is committed to the research of the most efficient and practical computer problem solutions.

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