By AOMEI / Last Updated June 22, 2020

About the Windows Server Backup Retention Period

Many people use Windows Server Backup to backup their servers and files. However, after running backups for a while, they do have some doubts. Why did Windows Server Backup not doing incremental backup though the incremental backup is configured? Why did it only keep one backup in the backup drive? How did the backup disk become full?

To break these down, you must understand the Windows Server Backup retention policy. Windows Server Backup has an automatic disk usage management function that will delete old backup versions when there is no enough space for the current backup. The retention policy is a certain rule to determine which backups to delete.

How Does the Windows Server Backup Retention Policy Works?

As you know, Windows Server Backup saves the backup versions in volume shadow copies by creating a shadow copy of the backup volume after a new backup is complete. Since the old backup versions are saved in shadow copies, you cannot delete it in File Explorer and you can only see the latest backup saved as a VHD file or VHDX file(since Windows Server 2012).

To save the shadow copies, Windows Server Backup will locate a certain space called diff area. If the program detects that the backup drive has insufficient space for the new backup to come, it will automatically delete the oldest backup version to free some space by shrinking the diff area.

Nevertheless, it will stop shrinking the allocated space for shadow copies when the diff area is about 1/8 of the backup volume size. Therefore, your backup will fail because of the backup disk full. When the backup disk gets filled, you can use WBadmin delete backup to delete old backups to free up space.

Since there is no way to create volume shadow copy of a network shared folder, scheduled backups on network location will only be performed as full backup. What’s worse, the new backup will overwrite the previous one, which is to say that you may have none backup if the backup fails in the middle.

Therefore, the Windows Server Backup retention period is not referring to network backup. If you need a better backup retention policy or prefer network backup solution, you can use third-party backup software for Windows Server instead of Windows Server Backup.

Windows Server Backup Retention Policy Best Practices – Specify Backup Retention Period

To make backup retention policy best practices, you can use AOMEI Backupper Server. It’s one professional Windows Server Backup program for Windows Server 2003, 2008, 2011, 2012, 2016, 2019 (including R2), SBS 2003, 2008, 2011 and Windows PC systems.

  • It allows you to backup system, files, partitions, and disks to any locations shown in File Explorer (including network location).

  • It gives you 5 ways of old backups cleanup, which you can specify backup retention period depending on your needs.

  • It enables you to have as many scheduled backup tasks followed by full/incremental/differential backup as you like.

  • Besides, you can set up an email notification to notify you whether the backup is complete or failed.

With the intuitive interface, AOMEI Backupper Server makes it easy enough to manage Server backup. Next, let’s start to see how to specify Windows Server backup retention period.

1. Download, and run this server backup tool.

Download Free Trial Win 10/8.1/8/7 & Server
Secure Download

2. Under the Backup tab, you can see four types of backup. Select System Backup here as an example.

System Backup

3. Since the program will include the system related items into the backup automatically, click the marked box to decide where you want to put the image backups.

Select Path

4. Click on the “Schedule” button down the window to create a scheduled backup.

Schedule Settings General

✍Daily/Weekly/Monthly: To backup your Windows Server continually, set the backup running daily, weekly, monthly to avoid backing up the repeated content manually or forgetting to backup.
✍Event Triggers: You could trigger the backup event to perform by the following events: User logon, User logoff, System startup, System shutdown.
USB plug in: Once detecting the source or destination USB device of the task is plugged in, AOMEI Backupper will automatically back up the data on the USB or backup local data to USB device. It’s kind of simple and flexible.
✍Real-time Sync: If you would like to sync files to other locations as soon as they changed, please try real time file sync feature to make your files stay up to date.

Then click Scheme -> Enable Backup Scheme to select a backup scheme and specify the number of backups to retain referring to the backup retention policy template.

Specify Windows Server Backup Retention Period

Tip: There are 5 schemes to help you to delete old backup image to free up space: Full Backup Scheme, Incremental Backup Scheme, Differential Backup Scheme, Space Management Scheme, Other Backup Scheme.

5. At last, click Start Backup to make this backup task on schedule.

Start Backup

If your server happens to be in serious situation, you can easily restore your server to an earlier state, and restore to dissimilar hardware is also supported. As a conclusion, if you are not comfortable with the Windows Server Backup retention policy, AOMEI Backupper is your best backup program for your Windows Server 2008/2012/2016/2019.


Now you know the Windows Server backup retention period policy and backup retention policy best practices. With AOMEI Backupper Server, there is no problem to create incremental backup to network location and it will help you delete old backups in your desired way. Go for it now and discover more!

If you want to protect unlimited PCs and servers within your company, you may choose AOMEI Backupper Technician Plus. It offers unlimited billable technical services to clients. It also enables you to copy installation directory for portable version creation.