How does Automatic disk usage management work?

Windows Server Backup (WSB) uses automatic disk usage management that can automatically delete old backups to free up disk space. Theoretically, there is no way to cause Windows Server Backup disk full. However, theory is not practice. After running scheduled backups for a while, it is likely that you may find that backup fails because there is not enough space on the disk.

Windows Server Backup would not overwrite old backups, to free space, WSB will shrink the space allocated for snapshots and delete the corresponding backups. WSB allows you to keep shrinking the space for snapshots till it is around 1/8 of the target disk size. Then you will find that your backup disk is full.

How to fix Windows Server 2008/2012/2016 backup disk full?

Since Windows Server Backup Automatic Disk Usage Management fails to function, to make your scheduled backup run again when the backup disk is full, you can add a larger disk as the backup disk or manually free some disk space for creating new backups. Windows Server 2012 or later versions of Windows Server, can use wbadmin delete backups command to delete one or more backups.

The syntax is WBADMIN DELETE BACKUP -keepVersion: -BackupTarget: . However, Windows Server 2008/2008 R2 only allows you to delete system state backup with WBadmin. If it is not system state backups that occupy the room of backup disk, then you can delete some snapshots from command line.

To delete snapshots, you can use diskshadow.exe. You can type Diskshadow.exe in the Run box or Start box, and press Enter to open Diskshadow.exe. Then run the following command:

delete shadows oldest

Delete Shadow

You can use drive letter or volume GUID to specify the backup target location. By default, the backup disk has no drive letter, but you can manually assign a drive letter with Disk Management. To see the volume GUID, you can run the command:



The next time backup disk is full, you can repeat these operations to clean up windows server backup. If you want to fix this problem once for all, it is recommended to try a different backup program.

Long-term solution | Avoid Windows Server Backup drive full

A dedicated Windows Server backup program, AOMEI Backupper Server is one powerful Windows Server Backup (WSB) alternative. It provides 4 types of backup solutions, System Backup, Disk Backup, Partition Backup, and File Backup.

  • Its Disk Space Management can help you to automatically delete the previous image backups in five different schemes. Therefore, you will never see Windows Server Backup filling up drive.

  • Compared to WSB can only create one daily or more frequent daily backup task, it allows you to set multiple backup schedules to let it backup daily/weekly/monthly.

  • You can also run scheduled backup tasks followed by full/incremental/differential backups.

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.

Let’s see how it works:

1. Download, install and open this Windows Server backup software.

2. Under the Backup tab, choose one type of backup that you need. The most often used backup solution System Backup will be taken as an example here.

System Backup

3. System Backup will automatically include the partitions containing system and boot files into the backup. Click to choose a target location to save the image backups.

Select Path

4. Click Schedule to configure a schedule for the backup task. Then click the Scheme option to enable Disk Space Management. Select one of the 5 types that suits your needs. Each scheme has dynamic graphics to show you how it works.

Backup Scheme

5. Click Start Backup to finish creating this backup schedule.

Start Backup


When you meet Windows Server Backup disk full problem, you can try to delete some snapshots from command line to free up space. However, as long as you keep using WSB to create backup, you would meet the drive full issue now and then.

If you want to fix the problem once for all, just try AOMEI Backupper Server. With the help of Disk Space Management, you will never find the Windows Server backup disk full. Besides, the image backups created with AOMEI Backupper can be easily restored to the original location or other location, and even restore to dissimilar hardware computer.