By Nicky / Last update December 22, 2020

Does Windows Server Backup delete old backups?


I have a Server 2012 (not R2) Hyper-V Host server using Windows Server Backup (WSB) to back up about 670 GB of data to three 1 TB USB hard drives, rotated weekly. The server was installed July 2013 and has been happily backing up to the backup drives until about a month ago. Now the backups are failing because the backup drives are out of space.


How do I configure the backup deletion policy introduced in Server 2012?

What exactly, if anything, has changed in Server 2012's handling of old backups created with Windows Server Backup when the backup drive runs out of space?

Backup version and space management in Windows Server Backup

Windows Server Backup automatic disk usage management was first introduced in Windows Server 2008 and later inherited in new version to manage disk space for schedule backup. It will shrink the storage space that allocated for snapshots (called diff area) to create space for new backups. Once the diff area gets shrunk, old snapshots, as well as corresponding backup versions get deleted.

But after running scheduled backups a couple of times, you still meet the backup error, Windows Server Backup does not delete old backups. This is the limitation of automatic disk usage management. To be specific, WSB will limit the the size of diff area to 1/8 target volume size, at this time WSB will not shrink the space and the backup task fails. And it does not work for external hard drive.

If this is your case, you can choose to manually delete old backup with Windows Server Backup command line - Wbadmin or make the deletion automatically with professional disk space manager - AOMEI Backupper Server. Please keep reading below to get details.

Windows Server Backup overwrite old backups maually with command line

If WSB does not delete old backup automatically, you may need to do this manually. Here you will learn how to use Wbadmin delete backup including system state backup and non-system state backup. Get the details below.

# Delete system state backup

Wbadmin provides 3 different parameters to help you specify the way to delete backups per your needs.

  • -version: to delete specific version(s).

  • -keepVersions: to delete all backups but the specified ones.

  • -deleteOldest: delete the oldest backup.

For example, to delete all the system backups but the specified one “3”, you could open the Command Prompt window and type the following command line. After that, please remember to press Enter to start this operation.
wbadmin delete systemstatebackup -keepVersions:3

Command Prompt 1

Note: As the name suggests, this command line deletes backup sthat only contain system state backup, otherwise you will receive error message, saying, "ERROR - No system state backups were found.
This command can be used to delete backups that only contain the system state." Thus, please ensure you have a separate system state backup.

# Delete non-system state backup

For example, to delete old backups in Windows Server 2012 that was taken on May the fourth evening at18:25, copy and paste the command to make it run.
Wbadmin delete backup -version: 05/04/2015-18:25 -backupTarget: G: machine: Win-9814GD4FH95

Notes :
-backupTarget: delete the system state backup stored on specific volume.
-machine: is only needed when you have backed up many computers to the same location.

This command line"Wbadmin delete backup" can still be used to perform Windows Server 2016/2019/2020 delete old backups, but you cannot use it on Windows Server 2008 R2 and previous version. Fortunately, there is still a workaround to delete old backup, it's command line utility - DiskShadow.exe.

For example, to delete old backups in Windows Server 2008 R2, type “DiskShadow.exe” in command prompt(Admin) and press Enter, then input the command line "delete shadows oldest G:” to start the deletion. The parameter “G” has to be replaced with your backup drive letter or volume GUID.

Command Prompt 2

But some users report that the “DiskShadow.exe” command line utility only supports deleting all the backups or the oldest, which force you to run it multiple times to overwrite more than one unwanted backup.

In addition, it still is difficult for many users to learn the parameters to delete old backups. This may take a long time but you may also use the command line incorrectly, eventually leading to irreversible data loss.

Therefore, it's suggested to use an easier way to achive this goal. You could consider using GUI-based AOMEI Backupper Server to manage disk space automatically with its "Backup Scheme" feature, saving much time and effort.

More flexible way to let Windows Server delete old backups automatically

Here you will use "Backup Scheme" in AOMEI Backupper Server to delete old backups automatically. You can set specific numbers of backups or backup cycles you want to retain. Once it reaches the specified value, this software will delete the oldest backup or all the backups in the previous backup cycle to free up space to retain backups.

For IT technicians or small and medium-sized companies, its advanced version AOMEI Backupper TechPlus will be a better choice. You can use it to continuously protect data and system on unilimited PCs and servers within one company, provide billable technical support as a service to unlimited clients and copy installation directory to create portable version.

Well then, let's start to perform Windows Server 2003/2008/2012/20162019/2020(including the R2 vesion) delete old backups in simple steps. In the first of place, download AOMEI Backupepr Server and install it on your server computer. Meanwhile, please prepare a storage device to store backup image, you can any recognized storage, such as, internal hard drive, external hard drive, network drive, cloud drive etc.

Download Freeware Windows Server 2020/2019/2016/2012/2008/2003
Secure Download

1. Connect the prepared storage to your server computer and be sure it can be detected. Then, launch server backup software - AOMEI Backupper Server, choose System Backup under Backup tab.

System Backup

2. The program will choose system and boot-related partition(s) automatically. You just need to select a destination location path to save the image backups. You can backup Windows Server to external hard drive, network share, NAS etc.

Select Backup Destination

3. Click “Schedule” and select one or more backup settings according to your needs.

  • Daily/Weekly/Monthly backup: It allows you to backup system automatically per day/weekly/monthly.

  • Event triggers: It allows you to backup system at specific event, you have 4 choices, namely, system startup, system shutdown, user logon, user logoff.

  • USB plug in: It's a flexible feature for users to automatically backup system to USB drive when it's plugged in.

  • Full/Incremental/Differential backup: It allows you to backup only changes after the first full backup, which takes less backup time and occupies less backup disk space.

Schedule Settings General

4. Click “Scheme” and “Enable Backup Scheme”, then you will see 5 backup schems. Select one of them and set set the number of backups or backup cycles you want to retain. Please note that the scheme and schedule need to be consistent, otherwise this software will run the scheduled backup in the way of scheme.

Backup Scheme

5. Confirm the backup settings and click Start Backup to start this task. Then, it will automatically delete old backup in Windows Server when the specific value you set is reached.

• Don't maually delete backups of the scheduld incremental backup. If you mistakenly delete one of the backups in a backup set, these backups will be invalid and you cannot use it to restore computer to an earlier date. That's because scheduled incremental backup requires all the backups in the backup set to be intact.
• It's suggested to create a bootable media for your computer, so you can restore it even if it's unbootable. And you can use it to on any PCs and servers, such as, Windows Server 2020/2019/2012/2008/2003 including the R2 version and Windows 10/8/7/XP/Vista.

Final words

Windows Server backup automatic disk usage management can help you delete old backup in Windows Server 2008/2008R2/2012(R2)/2016/2019/2020 sometimes. But when the diff. area reaches 1/8 of target disk space, it will not work. At this time, you need to manually perform Windows Server Backup delete old backups.

Here are two useful ways to achieve this goal, you can use command line Wbadmin or DiskShadow.exe, professional disk space manager - AOMEI Backupper Server. Honestly, the previous one has some limitations you cannot ignore and it's difficult for many users to learn and use. Therefore, it's wise to use AOMEI Backupper Server to delete old backup automatically.

In addition, it still has multiple features to benefit you, such as, schedule backup at daily/weekly/monthly, event triggers, USB plug in, incremental/differential backup, universal restore, create bootable media etc.