By Ivy / Last update February 2, 2021

Need help: Windows Server 2012 (R2) backup disk full

“I create a schedule backup in Windows Server 2012 using Windows Server Backup. My backup drive is 3TB hard drive. A few days ago, I receive a alter 'Free space is low in Server Backup. If you ignore this alter, the old backups on the backup disk will be overwritten by the new backups', so I ignored it.
But, last night, I receive another alert 'A scheduled backup did not finish successfully. The scheduled backup did not finish successfully and returned the following error code: 2155348326 Windows Backup encountered an error when writing data to the backup target. Detailed error: There is not enough space on the disk.'
The backup disk is indeed full. I’m confused. Why the old backup wasn’t overwritten as promised? Is there any way to get backups to overwrite? I just want to keep recent backups. Thanks very much. ”

Windows Server 2012 Backup Disk Full

In Windows Server Backup(WSB), there is a feature called automatic disk usage management, which will automatically reuse the space occupied by older backups when creating new backups.

To get more space for new backup, it will shrink the storage space allocated for snapshots (called diff area ). But there is an exception, if the backup disk space is less than 1/8, WSB will not delete backups automatically. This is why Windows Server 2012 backup drive full.

At this time, you need to delete old backup manually. And I will introduce 5 useful ways to help you, please keep reading below to learn them.

Method 1: Windows Server 2012 Backup Delete Old Copies using vssadmin

Windows Server Backup stores backup versions in volume shadow copies using VSS and it will retain the state of the storage volume as a “backup version” or “point-in-time” of the backup, So you can delete the shadow copies where the backup exists. Below is the detailed steps.

Step 1. Open cmd as administrator and type the following command to get the backup versions.

wbadmin get versions -backuptarget: (Please replace the with its drive letter.)

Step 2. Delete old backup version using the following command.

vssadmin delete shadows /for=x: /oldest (Please replace the x with drive letter of the backup drive.)

Step 3. Type exit the leave this window.

Besides, you still can use diskshadow and delete shadows oldest x: to delete old copies in Windows Server 2012(R2). PLEASE remember to start from the oldest instead of backup versions in the middle, or you may not get free space.

Method 2: Wbadmin Delete Old Backup | System State Backup

In Windows Server 2012(R2), you can use wbadmin to delete system state backup created by WSB. It can specify the backups with 3 different parameters, including [-version], [-keepVersions], [-deleteOldest].

Step 1. Learn the meaning of deletion parameters you will use.

[-version]: To delete specific version(s)

[-keepVersions]: To delete all backups but the specified ones

[-deleteOldest]: To delete the oldest backup.

Step 2. Open cmd and run as administrator. Then, delete backup copies with the following commands.

Example one: To delete the backup created at 18:25 06/08/2019, type as "wbadmin delete systemstatebackup -version: 06/08/2019-18:25".

Example two: To delete all system state backups, except the latest 10 backups, input "wbadmin delete systemstatebackup -keepVersions:10".

Example three: To delete the oldest system state backup stored on disk E, copy and paste "wbadmin delete systemstatebackup -backupTarget:E: -deleteOldest".

Note: -backupTarget only needs to be specified for locating backups that are not of the local computer.

Method 3: Wbadmin Delete Old Backup | Non-System State Backup

Wbadmin command line is also applicable to delete non-system state backup, but it is limited to Windows Server 2012 and new system.

Step 1. Run cmd as admministrator. Then, you can start to delete backup copies with the following command.

To delete backup created at 06:25 06/08/2019, type as:

wbadmin delete backup -keepVersion:11/10/2015-06:48 -BackupTarget:F:machine:WIN-9814GD4FH95

Note: -machine is only needed when you have backed up many computers to the same location.

Step 2. Wait untill the process is 100% completed, click X to exit.

Method 4: Windows Server Backup Clean Up Old Backups using shadow copies

Except for deletion, changing the usage space of shadow copies also help. The detailed steps are below, please try it yourself.

Step 1. Assign a drive letter for your backup drive if it does not have. Then, go to File Explore.

Step 2. Right-click the backup drive and select Manage Shadow Copies.

Step 3. Change the maximum size for the Shadow Copies, such as, 15%.

Method 5: Windows Server 2012 Backup and Cleanup using AOMEI Backupper Server

Windows Server Backup not deleting old backups is an annoying problems for many users, but there is nothing feasible except manual deletion. Not always like this, you could use a professional software integrated with backup and deletion.

Here I strongly recommend you AOMEI Backupper Server, which not only helps schedule backup system/disk/partition/file, but also manage backup disk space to ensure that there is always enough space for backup.

Then, learn detailed steps below to fix Windows Server 2012 backup disk full completely. Also, these steps are also applicable to clean up old backups in Windows Server 2003/2008(R2)/2016(R2)/2019 and Windows 10/8/7/XP/Vista.

Step 1. Be sure the backup drive is connected and can be detected. Then, free download AOMEI Backupper Server and install it.

Download Free Trial Windows Server 2012(R2)/2016/2019
Secure Download

Step 2. Launch this software, you will see its deep-blue screen. Click Backup and System Backup subsequently, it will automatically select the boot-related drive(s) required to start Windows.

System Backup

Step 3. Click where the arrow point and then select Computer or This PC to select the backup drive.

Select Path

Step 4(Required). Then, you need to set the schedule backup and backup retention. Please be sure the backup scheme is in consistent with schedule settings, otherwise this task will execute according to backup scheme.

Click Schedule and select daily/weekly/monthly plus full/incremental/differential backup to backup only changes since the last full backup, which saves much disk space and greatly reduces the backup time.

Also, you could use event triggers to backup system at specific event, such as, system startup, system shutdown, user logon or user logoff.

In addition, if your backup drive is USB drive, you could consider using "USB Plug in". It will automatically backup flash drive when plugged in, even without manually openning this software.

General Settings

Click Scheme and Enable Backup Scheme, then you will see 5 options under the drop-down menu. All of these backup scheme can help them delete old backups in Windows Server 2012, but the rules are different. Please check them in this software and select one per your needs.

Backup Scheme

Step 5. After that, you will go back to the main page of System Backup. Confirm all the selected items and click Start Backup to backup and cleanup.

Wrapping things up

"Windows Server Backup failed not enough space on disk" may be because the backup disk space is less than 1/8 of its own, thus you can choose to manually delete old backup using command line or try a professional backup software integrated with deletion.

But honestly, command line is complicated for majority of users to learn and use. Therefore, if you are not an IT technitian, it's suggested to fix Windows Server 2012 backup disk full using GUI-based backup software like AOMEI Backupper Server. It allows you to complete the whole process without any worries. You just need to set the schedule backup and backup retention once, then this software will take care of everything.

If you want to backup unlimited PCs and servers within one company, you could consider using AOMEI Backupper TechPlus. And it supports all features in AOMEI Backupper Server, and is able to provides billable technical support as a service to unlimited clients as well. Don't hesitate, download it to have a try right now!